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  • Kinetics
  • American Association for the Advancement of Science (AAAS)  (239)
  • Wiley-Blackwell  (21)
  • American Chemical Society (ACS)
  • 1990-1994  (260)
Collection
Keywords
Publisher
  • American Association for the Advancement of Science (AAAS)  (239)
  • Wiley-Blackwell  (21)
  • American Chemical Society (ACS)
  • Springer  (25)
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Kinetics of formation of charge transfer complexes of poly(vinyl pyridines) with iodine, 7,7′8,8′-tetracyanoquinodimethane and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone by electronic spectroscopic studies (1994)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 5 (1994), S. 184-192 
    Details
    ISSN: 1042-7147
    Keywords: Poly(vinyl pyridine) ; Iodine ; DDQ ; TCNQ ; Charge-transfer complexes ; Kinetics ; electronic absorption spectra ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The kinetics of formation of charge transfer complexes of poly(4-vinyl pyridine), poly(2-vinyl pyridine), and poly(2-vinyl pyridine-co-styrene) with iodine, 7,7′,8,8′-tetracyanoquinodimethane and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone has been studied using electronic absorption spectroscopy. The charge transfer complexes of analogous low molecular weight donors, namely 2- and 4-picolines with the same set of acceptors have also been investigated for comparison. The composition and the equilibrium constants of the charge transfer complexes have been obtained. The equilibrium constant of the polymeric complexes is found to be higher than that of analogous complexes of the low molecular weight donors. A new method for determining the rate constants of the association and dissociation of the equilibrium involving the charge transfer complex formation has been proposed. The rate constants vary with the concentration of the acceptor. It indicates that the charge transfer complexes undergo a further reaction and hence the observed rate constants are not true but apparent rate constants. The charge transfer complexes have also been investigated by electron paramagnetic resonance spectroscopy.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1994.220050307
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  • 2
    Electronic Resource
    Electronic Resource
    Comparison of the Nucleophilicities of Alkynes and Alkenes. Quantitative Determination of the Nucleophilicities of Alkynes toward Carbenium Ions (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 525-531 
    Details
    ISSN: 0009-2940
    Keywords: Alkynes ; Alkenes ; Nucleophilicity ; Carbenium ions ; Vinyl cations ; Kinetics ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Relative reactivities of alkenes and alkynes toward diarylmethyl cations have been determined by direct rate measurements and by competition experiments in dichloromethane. At -70°C alkynes are found to be one to two orders of magnitude less reactive than analogously substituted alkenes (e.g. phenylacetylene/styrene), but the reactivity difference reduces strongly as the temperature is raised. The stereochemistry of the vinyl chlorides produced by addition of benzhydryl chlorides to alkynes is characterized.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941270311
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  • 3
    Electronic Resource
    Electronic Resource
    Thermally Initiated Free-Radical Chain Addition of Alkanes to Alkynes, II. Kinetics of the Addition of Cyclohexane to Phenylethyne under Supercritical Fluid Conditions (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 673-675 
    Details
    ISSN: 0009-2940
    Keywords: Radicals ; Addition ; Alkynes ; Kinetics ; Supercritical fluid conditions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the addition of cyclohexane (2) to phenylethyne (1) proceeding via 2-cyclohexyl-1-phenylethenyl radical (3) to give 1-cyclohexyl-2-phenylethene (4) was investigated in the temperature range from 260 to 340°C. The radical chain is initiated by a bimolecular reaction of cyclohexane with phenylethyne to give a cyclohexyl radical and a 1-phenylethenyl radical. The physical state of the reaction mixture was varied from liquid to supercritical and to gasphase conditions. No effect on the reaction rate constant near the critical point was observed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941270416
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  • 4
    Electronic Resource
    Electronic Resource
    Erzeugung von 2-substituierten 1-Ethenyl-Kationen aus Ethylendiazonium-Salzen (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 933-939 
    Details
    ISSN: 0009-2940
    Keywords: Ethylenediazonium salts, thermal stability of, thermal degradation of ; Ethenyl cations, generation of, rearrangement of, interception of ; Kinetics ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermal decomposition of 2-substituted ethylenediazonium salts 1a-d produces the corresponding 1-ethenyl cations 2a-d as short-lived intermediates. The primary vinyl cation 2d or the rearranged and energetically favored analogues 3a-c of 2a-c are intercepted by chloride to give the decomposition products 4d and 5a-c, respectively. The generation of 4d and 5a-c as well as a kinetic study of the thermolysis reaction provide no indication that the elimination of nitrogen from 1a-d is occurring with the intermediate formation of cyclic cations 6 or 7.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941270522
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  • 5
    Electronic Resource
    Electronic Resource
    How Electrophilic are Ferrocenylmethyl Cations? Kinetics of their Reactions with π Nucleophiles and Hydride DonorsDedicated to Professor Dr. W. Tochtermann on the occasion of his 60th birthday. (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 2493-2498 
    Details
    ISSN: 0009-2940
    Keywords: Electrophilicity ; Ferrocenylmethylium ions ; Kinetics ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Second-order rate constants for the reactions of the ferrocenylmethylium ions 2a - e with silyl enol ethers, allylsilanes, allylstannanes, and hydride donors have been determined photometrically and conductometrically in dichloromethane. The ferrocenylmethylium ions 2a - d (fc-CHR+, R = H, Me, Ph, An) are slightly stronger electrophiles than the tropylium ion, and their electrophilic reactivities depend only slightly on the nature of R. The bis(ferrocenyl)methylium ion 2e is a considerably weaker electrophile, comparable to the tricarbonyl(cyclohexadienyl)iron cation.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941271221
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  • 6
    Electronic Resource
    Electronic Resource
    The Kinetics of Heterogeneous Electron Transfer Reaction in Polar Solvents (1994)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 33 (1994), S. 2131-2143 
    Details
    ISSN: 0570-0833
    Keywords: Electrochemistry ; Kinetics ; Electron transfer ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Data for heterogeneous electron transfer reactions obtained in the last ten years have been examined within the context of contemporary theory. Special attention is focused on systems for which rate constants and activation parameters are available as functions of solvents and of temperataure. The role of reactant structure in deteriming the kinetic parameters is also considered. Double layer effects both at unmodified and modified electrodes are discussed in detail. Experimental techniques, especially those suited to measuring fast reactions, are also outlined.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.199421311
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  • 7
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    Expanding the scope of RNA catalysis (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-06-24
    Description: The basic notions of transition state theory have been exploited in the past to generate highly selective catalysts from the vast library of antibody molecules in the immune system. These same ideas were used to isolate an RNA molecule, from a large library of RNAs, that catalyzes the isomerization of a bridged biphenyl. The RNA-catalyzed reaction displays Michaelis-Menten kinetics with a catalytic rate constant (kcat) of 2.8 x 10(-5) per minute and a Michaelis constant (Km) of 542 microM; the reaction is competitively inhibited by the planar transition state analog with an inhibition constant (Ki) value of approximately 7 microM. This approach may provide a general strategy for expanding the scope of RNA catalysis beyond those reactions in which the substrates are nucleic acids or nucleic acid derivatives.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Prudent, J R -- Uno, T -- Schultz, P G -- GM08352A/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Jun 24;264(5167):1924-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of California, Berkeley.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8009223" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Biphenyl Compounds/chemistry/metabolism ; Catalysis ; Kinetics ; Molecular Sequence Data ; Nucleic Acid Conformation ; Nucleic Acid Denaturation ; Polymerase Chain Reaction ; RNA, Catalytic/chemistry/*metabolism ; Stereoisomerism ; Temperature
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 8
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    A specific inhibitor of the epidermal growth factor receptor tyrosine kinase (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-08-19
    Description: A small molecule called PD 153035 inhibited the epidermal growth factor (EGF) receptor tyrosine kinase with a 5-pM inhibition constant. The inhibitor was specific for the EGF receptor tyrosine kinase and inhibited other purified tyrosine kinases only at micromolar or higher concentrations. PD 153035 rapidly suppressed autophosphorylation of the EGF receptor at low nanomolar concentrations in fibroblasts or in human epidermoid carcinoma cells and selectively blocked EGF-mediated cellular processes including mitogenesis, early gene expression, and oncogenic transformation. PD 153035 demonstrates an increase in potency over that of other tyrosine kinase inhibitors of four to five orders of magnitude for inhibition of isolated EGF receptor tyrosine kinase and three to four orders of magnitude for inhibition of cellular phosphorylation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fry, D W -- Kraker, A J -- McMichael, A -- Ambroso, L A -- Nelson, J M -- Leopold, W R -- Connors, R W -- Bridges, A J -- New York, N.Y. -- Science. 1994 Aug 19;265(5175):1093-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Parke-Davis Pharmaceutical Research, Division of Warner-Lambert Company, Ann Arbor, MI 48105.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8066447" target="_blank"〉PubMed〈/a〉
    Keywords: 3T3 Cells ; Animals ; Cell Transformation, Neoplastic/drug effects ; Epidermal Growth Factor/pharmacology ; Fibroblast Growth Factor 2/pharmacology ; Gene Expression/drug effects ; Humans ; Kinetics ; Mice ; Mitosis/drug effects ; Phosphorylation/drug effects ; Platelet-Derived Growth Factor/pharmacology ; Protein-Tyrosine Kinases/antagonists & inhibitors ; Quinazolines/*antagonists & inhibitors ; Receptor, Epidermal Growth Factor/*antagonists & inhibitors ; Tumor Cells, Cultured ; Tyrosine/metabolism
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 9
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    Two identical noninteracting sites in an ion channel revealed by proton transfer (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-09-23
    Description: The functional consequences of single proton transfers occurring in the pore of a cyclic nucleotide-gated channel were observed with patch recording techniques. These results led to three conclusions about the chemical nature of ion binding sites in the conduction pathway: The channel contains two identical titratable sites, even though there are more than two (probably four) identical subunits; the sites are formed by glutamate residues that have a pKa (where K(a) is the acid constant) of 7.6; and protonation of one site does not perturb the pKa of the other. These properties point to an unusual arrangement of carboxyl side-chain residues in the pore of a cation channel.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Root, M J -- MacKinnon, R -- 5 T32 GM083113/GM/NIGMS NIH HHS/ -- GM47400/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Sep 23;265(5180):1852-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Neurobiology, Harvard Medical School, Boston, MA 02115.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7522344" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Binding Sites ; Calcium Channels/metabolism ; Catfishes ; Electric Conductivity ; Hydrogen-Ion Concentration ; Ion Channel Gating ; Ion Channels/chemistry/genetics/*metabolism ; Kinetics ; Molecular Sequence Data ; Mutation ; *Protons ; Sodium/metabolism ; Xenopus
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 10
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    Stern-volmer in reverse: 2:1 stoichiometry of the cytochrome c-cytochrome c peroxidase electron-transfer complex (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-09-16
    Description: A reverse protocol for measurements of molecular binding and reactivity by excited-state quenching has been developed in which the quencher, held at a fixed concentration, is titrated by a photoexcitable probe molecule whose decay is monitored. The binding stoichiometries, affinities, and reactivities of the electron-transfer complexes between cytochrome c (Cc) and cytochrome c peroxidase (CcP) were determined over a wide range of ionic strengths (4.5 to 118 millimolar) by the study of photoinduced electron-transfer quenching of the triplet excited state of zinc-substituted Cc (ZnCc) by Fe3+CcP. The 2:1 stoichiometry seen for the binding of Cc to CcP at low ionic strength persists at the physiologically relevant ionic strengths and likely has functional significance. Analysis of the stoichiometric binding and rate constants confirms that one surface domain of CcP binds Cc with a high affinity but with poor electron-transfer quenching of triplet-state ZnCc, whereas a second binds weakly but with a high rate of electron-transfer quenching.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zhou, J S -- Hoffman, B M -- HL13531/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1994 Sep 16;265(5179):1693-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Northwestern University, Evanston, IL 60208-3113.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8085152" target="_blank"〉PubMed〈/a〉
    Keywords: Cytochrome c Group/chemistry/*metabolism ; Cytochrome-c Peroxidase/chemistry/*metabolism ; Electron Transport ; Ferric Compounds ; Kinetics ; Osmolar Concentration ; Oxidation-Reduction ; Zinc
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 11
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    Visualization of quantal synaptic transmission by dendritic calcium imaging (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-01-28
    Description: As changes in synaptic strength are thought to be critical for learning and memory, it would be useful to monitor the activity of individual identified synapses on mammalian central neurons. Calcium imaging of cortical neurons grown in primary culture was used to visualize the activation of individual postsynaptic elements by miniature excitatory synaptic currents elicited by spontaneous quantal release. This approach revealed that the probability of spontaneous activity differed among synapses on the same dendrite. Furthermore, synapses that undergo changes in activity induced by glutamate or phorbol ester treatment were identified.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Murphy, T H -- Baraban, J M -- Wier, W G -- Blatter, L A -- New York, N.Y. -- Science. 1994 Jan 28;263(5146):529-32.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7904774" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Calcium/*metabolism ; Cells, Cultured ; Cerebral Cortex ; Dendrites/*metabolism ; Glutamates/pharmacology ; Glutamic Acid ; Kinetics ; Microelectrodes ; Neuronal Plasticity ; Neurons/*physiology ; Phorbol Esters/pharmacology ; Rats ; Receptors, N-Methyl-D-Aspartate/physiology ; Synapses/*physiology ; *Synaptic Transmission ; Tetrodotoxin/pharmacology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 12
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    Control of kinetic properties of AMPA receptor channels by nuclear RNA editing (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-12-09
    Description: AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor channels mediate the fast component of excitatory postsynaptic currents in the central nervous system. Site-selective nuclear RNA editing controls the calcium permeability of these channels, and RNA editing at a second site is shown here to affect the kinetic aspects of these channels in rat brain. In three of the four AMPA receptor subunits (GluR-B, -C, and -D), intronic elements determine a codon switch (AGA, arginine, to GGA, glycine) in the primary transcripts in a position termed the R/G site, which immediately precedes the alternatively spliced modules "flip" and "flop." The extent of editing at this site progresses with brain development in a manner specific for subunit and splice form, and edited channels possess faster recovery rates from desensitization.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lomeli, H -- Mosbacher, J -- Melcher, T -- Hoger, T -- Geiger, J R -- Kuner, T -- Monyer, H -- Higuchi, M -- Bach, A -- Seeburg, P H -- New York, N.Y. -- Science. 1994 Dec 9;266(5191):1709-13.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Molecular Neuroendocrinology, University of Heidelberg, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7992055" target="_blank"〉PubMed〈/a〉
    Keywords: Alternative Splicing ; Amino Acid Sequence ; Animals ; Base Sequence ; Brain/embryology/*metabolism ; Cell Nucleus/metabolism ; Exons ; Glutamic Acid/pharmacology ; Glycine/genetics ; Introns ; Kinetics ; Membrane Potentials ; Molecular Sequence Data ; Oocytes ; PC12 Cells ; Patch-Clamp Techniques ; *RNA Editing ; Rats ; Rats, Wistar ; Receptors, AMPA/*genetics/*metabolism ; Recombinant Proteins/metabolism ; Xenopus
    Print ISSN: 0036-8075
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  • 13
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    Kinetics of molecular chaperone action (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-02-18
    Description: Molecular chaperones of the Hsp70 type transiently sequester unfolded segments of proteins and promote their correct folding. Target peptides were labeled with an environmentally sensitive fluorophore so that their binding to the molecular chaperone DnaK of Escherichia coli could be followed in real time. The two-step process was characterized by relaxation times of 27 seconds and 200 seconds with 2 microM DnaK and 0.1 microM ligand at 25 degrees C. In the presence of adenosine triphosphate, the formation of the complex was greatly accelerated and appeared to be a single-exponential process with a relaxation time of 0.4 second. The binding-release cycle of DnaK thus occurs in the time range of polypeptide chain elongation and folding and is too fast to be stoichiometrically coupled to the adenosine triphosphatase activity of the chaperone (turnover number, 0.13 per minute at 30 degrees C).〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schmid, D -- Baici, A -- Gehring, H -- Christen, P -- New York, N.Y. -- Science. 1994 Feb 18;263(5149):971-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Biochemisches Institut, Universitat Zurich, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8310296" target="_blank"〉PubMed〈/a〉
    Keywords: 2-Naphthylamine/analogs & derivatives ; Adenosine Triphosphatases/metabolism ; Adenosine Triphosphate/analogs & derivatives/pharmacology ; Amino Acid Sequence ; Aspartate Aminotransferases/metabolism ; Bacterial Proteins/*metabolism ; Binding Sites ; Enzyme Precursors/metabolism ; *Escherichia coli Proteins ; Fluorescent Dyes ; *HSP70 Heat-Shock Proteins ; Heat-Shock Proteins/*metabolism ; Kinetics ; Molecular Sequence Data ; Peptide Fragments/*metabolism
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 14
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    Stimulation of RNA polymerase II elongation by chromosomal protein HMG-14 (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-08-05
    Description: The high-mobility group protein 14 (HMG-14) is a non-histone chromosomal protein that is preferentially associated with transcriptionally active chromatin. To assess the effect of HMG-14 on transcription by RNA polymerase II, in vivo-assembled chromatin with elevated amounts of HMG-14 was obtained. Here it is shown that HMG-14 enhanced transcription on chromatin templates but not on DNA templates. This protein stimulated the rate of elongation by RNA polymerase II but not the level of initiation of transcription. These findings suggest that the association of HMG-14 with nucleosomes is part of the cellular process involved in the generation of transcriptionally active chromatin.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ding, H F -- Rimsky, S -- Batson, S C -- Bustin, M -- Hansen, U -- GM-36667/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Aug 5;265(5173):796-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Molecular Genetics, Dana-Farber Cancer Institute, Boston, MA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8047885" target="_blank"〉PubMed〈/a〉
    Keywords: Chromatin/metabolism ; HeLa Cells ; High Mobility Group Proteins/*physiology ; Humans ; Kinetics ; RNA Polymerase II/*metabolism ; Simian virus 40/genetics ; Templates, Genetic ; Transcription, Genetic/*physiology
    Print ISSN: 0036-8075
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 15
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    Blockage of NF-kappa B signaling by selective ablation of an mRNA target by 2-5A antisense chimeras (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-08-05
    Description: Activation of 2-5A-dependent ribonuclease by 5'-phosphorylated, 2',5'-linked oligoadenylates, known as 2-5A, is one pathway of interferon action. Unaided uptake into HeLa cells of 2-5A linked to an antisense oligonucleotide resulted in the selective ablation of messenger RNA for the double-stranded RNA (dsRNA)-dependent protein kinase PKR. Similarly, purified, recombinant human 2-5A-dependent ribonuclease was induced to selectively cleave PKR messenger RNA. Cells depleted of PKR activity were unresponsive to activation of nuclear factor-kappa B (NF-kappa B) by the dsRNA poly(I):poly(C), which provides direct evidence that PKR is a transducer for the dsRNA signaling of NF-kappa B.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Maran, A -- Maitra, R K -- Kumar, A -- Dong, B -- Xiao, W -- Li, G -- Williams, B R -- Torrence, P F -- Silverman, R H -- AI 28253/AI/NIAID NIH HHS/ -- AI 34039-02/AI/NIAID NIH HHS/ -- CA 44059/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1994 Aug 5;265(5173):789-92.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cancer Biology, Cleveland Clinic Foundation, OH 44195.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7914032" target="_blank"〉PubMed〈/a〉
    Keywords: Adenine Nucleotides/chemical synthesis/*pharmacology ; Base Sequence ; Endoribonucleases/metabolism ; Enzyme Activation ; HeLa Cells ; Humans ; Kinetics ; Molecular Sequence Data ; NF-kappa B/*antagonists & inhibitors ; Oligonucleotides, Antisense/chemical synthesis/*pharmacology ; Oligoribonucleotides/chemical synthesis/*pharmacology ; Protein-Serine-Threonine Kinases/*genetics ; RNA, Messenger/drug effects ; Signal Transduction/*drug effects ; eIF-2 Kinase
    Print ISSN: 0036-8075
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 16
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    Dynamics of the chaperonin ATPase cycle: implications for facilitated protein folding (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-07-29
    Description: The Escherichia coli chaperonins GroEL and GroES facilitate protein folding in an adenosine triphosphate (ATP)-dependent manner. After a single cycle of ATP hydrolysis by the adenosine triphosphatase (ATPase) activity of GroEL, the bi-toroidal GroEL formed a stable asymmetric ternary complex with GroES and nucleotide (bulletlike structures). With each subsequent turnover, ATP was hydrolyzed by one ring of GroEL in a quantized manner, completely releasing the adenosine diphosphate and GroES that were tightly bound to the other ring as a result of the previous turnover. The catalytic cycle involved formation of a symmetric complex (football-like structures) as an intermediate that accumulated before the rate-determining hydrolytic step. After one to two cycles, most of the substrate protein dissociated still in a nonnative state, which is consistent with intermolecular transfer of the substrate protein between toroids of high and low affinity. A unifying model for chaperonin-facilitated protein folding based on successive rounds of binding and release, and partitioning between committed and kinetically trapped intermediates, is proposed.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Todd, M J -- Viitanen, P V -- Lorimer, G H -- New York, N.Y. -- Science. 1994 Jul 29;265(5172):659-66.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉E. I. DuPont de Nemours and Company, Central Research and Development Department, Wilmington, DE 19880.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7913555" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphatases/*metabolism ; Bacterial Proteins/*metabolism ; Binding Sites ; Chaperonin 10 ; Chaperonin 60 ; Heat-Shock Proteins/*metabolism ; Kinetics ; Models, Chemical ; *Protein Folding ; Ribulose-Bisphosphate Carboxylase/metabolism
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  • 17
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    Rapid induction of Alzheimer A beta amyloid formation by zinc (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-09-02
    Description: A beta 1-40, a major component of Alzheimer's disease cerebral amyloid, is present in the cerebrospinal fluid and remains relatively soluble at high concentrations (less than or equal to 3.7 mM). Thus, physiological factors which induce A beta amyloid formation could provide clues to the pathogenesis of the disease. It has been shown that human A beta specifically and saturably binds zinc. Here, concentrations of zinc above 300 nM rapidly destabilized human A beta 1-40 solutions, inducing tinctorial amyloid formation. However, rat A beta 1-40 binds zinc less avidly and is immune to these effects, perhaps explaining the scarcity with which these animals form cerebral A beta amyloid. These data suggest a role for cerebral zinc metabolism in the neuropathogenesis of Alzheimer's disease.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bush, A I -- Pettingell, W H -- Multhaup, G -- d Paradis, M -- Vonsattel, J P -- Gusella, J F -- Beyreuther, K -- Masters, C L -- Tanzi, R E -- R01 AG11899-01/AG/NIA NIH HHS/ -- R01 NS30428-03/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1994 Sep 2;265(5177):1464-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Genetics and Aging, Massachusetts General Hospital, Boston.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8073293" target="_blank"〉PubMed〈/a〉
    Keywords: Alzheimer Disease/etiology/*metabolism ; Amyloid beta-Peptides/chemistry/*metabolism ; Animals ; Brain/metabolism ; Edetic Acid/pharmacology ; Humans ; Kinetics ; Mice ; Peptide Fragments/chemistry/*metabolism ; Rats ; Solubility ; Zinc/*metabolism/pharmacology
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  • 18
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    Peptide synthesis catalyzed by an antibody containing a binding site for variable amino acids (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-07-08
    Description: Monoclonal antibodies, induced with a phosphonate diester hapten, catalyzed the coupling of p-nitrophenyl esters of N-acetyl valine, leucine, and phenylalanine with tryptophan amide to form the corresponding dipeptides. All possible stereoisomeric combinations of the ester and amide substrates were coupled at comparable rates. The antibodies did not catalyze the hydrolysis of the dipeptide product nor hydrolysis or racemization of the activated esters. The yields of the dipeptides ranged from 44 to 94 percent. The antibodies were capable of multiple turnovers at rates that exceeded the rate of spontaneous ester hydrolysis. This achievement suggests routes toward creating a small number of antibody catalysts for polypeptide syntheses.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hirschmann, R -- Smith, A B 3rd -- Taylor, C M -- Benkovic, P A -- Taylor, S D -- Yager, K M -- Sprengeler, P A -- Benkovic, S J -- GM-45611/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Jul 8;265(5169):234-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of Pennsylvania, Philadelphia 19104.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8023141" target="_blank"〉PubMed〈/a〉
    Keywords: Antibodies, Catalytic/*metabolism ; Antibodies, Monoclonal/*metabolism ; Binding Sites, Antibody ; Dipeptides/*biosynthesis ; Esters ; Haptens ; Kinetics ; Leucine/analogs & derivatives/metabolism ; Molecular Conformation ; Phenylalanine/analogs & derivatives/metabolism ; Stereoisomerism ; Tryptophan/analogs & derivatives/metabolism ; Valine/analogs & derivatives/metabolism
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  • 19
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    DNA repair rates mapped along the human PGK1 gene at nucleotide resolution (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-03-11
    Description: The repair of cyclobutane pyrimidine dimers (CPDs), DNA lesions induced by ultraviolet light, was studied at nucleotide resolution. Human fibroblasts were irradiated with ultraviolet light and allowed to repair. The DNA was enzymatically cleaved at the CPDs, and the induced breaks along the promoter and exon 1 of the PGK1 gene were mapped by ligation-mediated polymerase chain reaction. Repair rates within the nontranscribed strand varied as much as 15-fold, depending on nucleotide position. Preferential repair of the transcribed strand began just downstream of the transcription start site but was most pronounced beginning at nucleotide +140 in exon 1. The promoter contained two slowly repaired regions that coincided with two transcription factor binding sites.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gao, S -- Drouin, R -- Holmquist, G P -- CA54773/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1994 Mar 11;263(5152):1438-40.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Beckman Research Institute of the City of Hope, Department of Biology, Duarte, CA 91010.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8128226" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Cells, Cultured ; *DNA Repair ; Exons ; *Genes ; HeLa Cells ; Humans ; Kinetics ; Phosphoglycerate Kinase/*genetics ; Promoter Regions, Genetic ; Pyrimidine Dimers/*metabolism ; Skin/metabolism/*radiation effects ; Transcription Factors/metabolism ; Transcription, Genetic ; Ultraviolet Rays
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 20
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    T cell receptor-MHC class I peptide interactions: affinity, kinetics, and specificity (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-08-12
    Description: The critical discriminatory event in the activation of T lymphocytes bearing alpha beta T cell receptors (TCRs) is their interaction with a molecular complex consisting of a peptide bound to a major histocompatibility complex (MHC)-encoded class I or class II molecule on the surface of an antigen-presenting cell. The kinetics of binding were measured of a purified TCR to molecular complexes of a purified soluble analog of the murine MHC class I molecule H-2Ld (sH-2Ld) and a synthetic octamer peptide p2CL in a direct, real-time assay based on surface plasmon resonance. The kinetic dissociation rate of the MHC-peptide complex from the TCR was rapid (2.6 x 10(-2) second-1, corresponding to a half-time for dissociation of approximately 27 seconds), and the kinetic association rate was 2.1 x 10(5) M-1 second-1. The equilibrium constant for dissociation was approximately 10(-7) M. These values indicate that TCRs must interact with a multivalent array of MHC-peptide complexes to trigger T cell signaling.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Corr, M -- Slanetz, A E -- Boyd, L F -- Jelonek, M T -- Khilko, S -- al-Ramadi, B K -- Kim, Y S -- Maher, S E -- Bothwell, A L -- Margulies, D H -- New York, N.Y. -- Science. 1994 Aug 12;265(5174):946-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Molecular Biology Section, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8052850" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Biosensing Techniques ; H-2 Antigens/*metabolism ; Histocompatibility Antigen H-2D ; Kinetics ; *Major Histocompatibility Complex ; Mice ; Molecular Sequence Data ; Oligopeptides/*metabolism ; Receptors, Antigen, T-Cell, alpha-beta/*metabolism ; Solubility
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  • 21
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    Mortality rates in a genetically heterogeneous population of Caenorhabditis elegans (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-02-04
    Description: Age-specific mortality rates in isogenic populations of the nematode Caenorhabditis elegans increase exponentially throughout life. In genetically heterogeneous populations, age-specific mortality increases exponentially until about 17 days and then remains constant until the last death occurs at about 60 days. This period of constant age-specific mortality results from genetic heterogeneity. Subpopulations differ in mean life-span, but they all exhibit near exponential, albeit different, rates of increase in age-specific mortality. Thus, much of the observed heterogeneity in mortality rates later in life could result from genetic heterogeneity and not from an inherent effect of aging.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Brooks, A -- Lithgow, G J -- Johnson, T E -- K04-AG00369/AG/NIA NIH HHS/ -- R01-AG08332/AG/NIA NIH HHS/ -- R01-AG10248/AG/NIA NIH HHS/ -- New York, N.Y. -- Science. 1994 Feb 4;263(5147):668-71.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute of Behavioral Genetics, University of Colorado, Boulder 80309.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8303273" target="_blank"〉PubMed〈/a〉
    Keywords: Aging ; Animals ; Caenorhabditis elegans/genetics/*physiology ; *Genetic Variation ; Kinetics ; Longevity/genetics ; Mortality
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  • 22
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    Low-barrier hydrogen bonds and enzymic catalysis (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-06-24
    Description: Formation of a short (less than 2.5 angstroms), very strong, low-barrier hydrogen bond in the transition state, or in an enzyme-intermediate complex, can be an important contribution to enzymic catalysis. Formation of such a bond can supply 10 to 20 kilocalories per mole and thus facilitate difficult reactions such as enolization of carboxylate groups. Because low-barrier hydrogen bonds form only when the pKa's (negative logarithm of the acid constant) of the oxygens or nitrogens sharing the hydrogen are similar, a weak hydrogen bond in the enzyme-substrate complex in which the pKa's do not match can become a strong, low-barrier one if the pKa's become matched in the transition state or enzyme-intermediate complex. Several examples of enzymatic reactions that appear to use this principle are presented.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cleland, W W -- Kreevoy, M M -- GM 18938/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Jun 24;264(5167):1887-90.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute for Enzyme Research, University of Wisconsin, Madison 53705.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8009219" target="_blank"〉PubMed〈/a〉
    Keywords: Aconitate Hydratase/chemistry/metabolism ; Binding Sites ; Carboxypeptidases/chemistry/metabolism ; *Catalysis ; Citrate (si)-Synthase/chemistry/metabolism ; Enzymes/*metabolism ; *Hydrogen Bonding ; Isomerases/chemistry/metabolism ; Kinetics ; Orotidine-5'-Phosphate Decarboxylase/chemistry/metabolism ; Racemases and Epimerases/chemistry/metabolism ; Thermolysin/chemistry/metabolism
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  • 23
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    Antibody catalyzed cationic cyclization (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-05-27
    Description: Two major goals for the design of new catalysts are the facilitation of chemical transformations and control of product outcome. An antibody has been induced that efficiently catalyzes a cationic cyclization in which an acyclic olefinic sulfonate ester substrate is converted almost exclusively (98 percent) to a cyclic alcohol. The key to the catalysis of the reaction and the restriction of the product complexity is the use of antibody binding energy to rigidly enforce a concerted mechanism in accord with the design of the hapten. Thus, the ability to direct binding energy allows the experimenter to dictate a reaction mechanism which is an otherwise difficult task in chemistry. New catalysts for cationic cyclization may be of general use in the formation of carbon-carbon and carbon-heteroatom bonds leading to multi-ring molecules including steroids and heterocyclic compounds.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Li, T -- Janda, K D -- Ashley, J A -- Lerner, R A -- GM-43858/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 May 27;264(5163):1289-93.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Scripps Research Institute, Department of Molecular Biology, La Jolla, CA 92037.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8191282" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antibodies, Catalytic/*chemistry ; Antibodies, Monoclonal/chemistry ; Catalysis ; Cations/*chemistry ; Chromatography, Gas ; Cyclization ; Haptens ; Kinetics ; Mice ; Organosilicon Compounds/*chemistry ; Sulfanilic Acids/*chemistry
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  • 24
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    Selection of guide sequences that direct efficient cleavage of mRNA by human ribonuclease P (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-03-04
    Description: Any RNA, when in a complex with another oligoribonucleotide known as an external guide sequence (EGS), can become a substrate for ribonuclease P. Simulation of evolution in vitro was used to select EGSs that bind tightly to a target substrate messenger RNA and that increase the efficiency of cleavage of the target by human ribonuclease P to a level equal to that achieved with natural substrates. The most efficient EGSs form transfer RNA precursor-like structures with the target RNA, in which the analog of the anticodon stem has been disrupted, an indication that selection for the optimal substrate for ribonuclease P yields an RNA structure different from that of present-day transfer RNA precursors.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Yuan, Y -- Altman, S -- AI31876/AI/NIAID NIH HHS/ -- GM19422/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Mar 4;263(5151):1269-73.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, Yale University, New Haven, CT 06520.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8122108" target="_blank"〉PubMed〈/a〉
    Keywords: Anticodon/chemistry/metabolism ; Base Sequence ; Chloramphenicol O-Acetyltransferase/genetics ; Endoribonucleases/*metabolism ; Humans ; Kinetics ; Magnesium/pharmacology ; Molecular Sequence Data ; Nucleic Acid Conformation ; Oligoribonucleotides/chemistry/*metabolism ; RNA Precursors/chemistry/metabolism ; RNA, Catalytic/*metabolism ; RNA, Guide/chemistry/*metabolism ; RNA, Messenger/chemistry/*metabolism ; RNA, Transfer/chemistry/metabolism ; Ribonuclease P ; Thermodynamics
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  • 25
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    Kinetic intermediates in RNA folding (1994)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1994-08-12
    Description: The folding pathways of large, highly structured RNA molecules are largely unexplored. Insight into both the kinetics of folding and the presence of intermediates was provided in a study of the Mg(2+)-induced folding of the Tetrahymena ribozyme by hybridization of complementary oligodeoxynucleotide probes. This RNA folds via a complex mechanism involving both Mg(2+)-dependent and Mg(2+)-independent steps. A hierarchical model for the folding pathway is proposed in which formation of one helical domain (P4-P6) precedes that of a second helical domain (P3-P7). The overall rate-limiting step is formation of P3-P7, and takes place with an observed rate constant of 0.72 +/- 0.14 minute-1. The folding mechanism of large RNAs appears similar to that of many multidomain proteins in that formation of independently stable substructures precedes their association into the final conformation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zarrinkar, P P -- Williamson, J R -- New York, N.Y. -- Science. 1994 Aug 12;265(5174):918-24.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Massachusetts Institute of Technology, Cambridge 02139.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8052848" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Base Sequence ; Introns ; Kinetics ; Magnesium/metabolism/pharmacology ; Models, Chemical ; Molecular Sequence Data ; *Nucleic Acid Conformation ; Nucleic Acid Hybridization ; Oligonucleotide Probes ; RNA, Catalytic/*chemistry/metabolism ; RNA, Protozoan/*chemistry ; Ribonuclease H/metabolism ; Temperature ; Tetrahymena/*genetics
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  • 26
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    Mutational isolation of a sieve for editing in a transfer RNA synthetase (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-04-08
    Description: Editing reactions are essential for the high fidelity of information transfer in processes such as replication, RNA splicing, and protein synthesis. The accuracy of interpretation of the genetic code is enhanced by the editing reactions of aminoacyl transfer RNA (tRNA) synthetases, whereby amino acids are prevented from being attached to the wrong tRNAs. Amino acid discrimination is achieved through sieves that may overlap with or coincide with the amino acid binding site. With the class I Escherichia coli isoleucine tRNA synthetase, which activates isoleucine and occasionally misactivates valine, as an example, a rationally chosen mutant enzyme was constructed that lacks entirely its normal strong ability to distinguish valine from isoleucine by the initial amino acid recognition sieve. The misactivated valine, however, is still eliminated by hydrolytic editing reactions. These data suggest that there is a distinct sieve for editing that is functionally independent of the amino acid binding site.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schmidt, E -- Schimmel, P -- GM 15539/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Apr 8;264(5156):265-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8146659" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphate/metabolism ; Binding Sites ; Escherichia coli/enzymology ; Isoleucine/*metabolism ; Isoleucine-tRNA Ligase/chemistry/genetics/*metabolism ; Kinetics ; Mutation ; Protein Structure, Secondary ; *RNA Editing ; RNA, Transfer, Ile/metabolism ; Valine/*metabolism
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  • 27
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    Protein-protein interactions contributing to the specificity of intracellular vesicular trafficking (1994)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1994-02-25
    Description: Intracellular vesicles destined to fuse with the plasma membrane and secrete their contents must have a mechanism for specifically interacting with the appropriate target membrane. Such a mechanism is now suggested by the demonstration of specific interaction between vesicular proteins and plasma membrane proteins. The vesicle-associated membrane proteins (VAMPs) 1 and 2 specifically bind the acceptor membrane proteins syntaxin 1A and 4 but not syntaxin 2 or 3. The binding site is within amino acids 194 to 267 of syntaxin 1A, and the approximate equilibrium dissociation constants is 4.7 x 10(-6) molar. These data suggest a physical basis for the specificity of intracellular vesicular transport.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Calakos, N -- Bennett, M K -- Peterson, K E -- Scheller, R H -- New York, N.Y. -- Science. 1994 Feb 25;263(5150):1146-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Stanford University Medical Center, CA 94305.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8108733" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Antigens, Surface/*metabolism ; Binding Sites ; Cell Line ; Cell Membrane/metabolism ; Cytoplasm/metabolism ; Haplorhini ; Kinetics ; Membrane Proteins/*metabolism ; Molecular Sequence Data ; Nerve Tissue Proteins/*metabolism ; R-SNARE Proteins ; Recombinant Fusion Proteins/metabolism ; Synaptic Vesicles/*metabolism ; Syntaxin 1
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  • 28
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    Magnetic field effects on B12 ethanolamine ammonia lyase: evidence for a radical mechanism (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-02-18
    Description: A change in radical pair recombination rates is one of the few mechanisms by which a magnetic field can interact with a biological system. The kinetic parameter Vmax/Km (where Km is the Michaelis constant) for the coenzyme B12-dependent enzyme ethanolamine ammonia lyase was decreased 25 percent by a static magnetic field near 0.1 tesla (1000 gauss) with unlabeled ethanolamine and decreased 60 percent near 0.15 tesla with perdeuterated ethanolamine. This effect is likely caused by a magnetic field-induced change in intersystem crossing rates between the singlet and triplet spin states in the [cob(II)alamin:5'-deoxyadenosyl radical] spin-correlated radical pair.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Harkins, T T -- Grissom, C B -- ES05728/ES/NIEHS NIH HHS/ -- New York, N.Y. -- Science. 1994 Feb 18;263(5149):958-60.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of Utah, Salt Lake City 84112.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8310292" target="_blank"〉PubMed〈/a〉
    Keywords: Deuterium ; Ethanolamine ; Ethanolamine Ammonia-Lyase/*metabolism ; Ethanolamines/metabolism ; Kinetics ; *Magnetics ; Photolysis ; Vitamin B 12/pharmacology
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  • 29
    Electronic Resource
    Electronic Resource
    Untersuchungen mit selektiven Abspaltungsreagenzien für ADPOC-geschützte Aminosäuren und Peptide (1993)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1993 (1993), S. 131-136 
    Details
    ISSN: 0170-2041
    Keywords: Adpoc-protecting group ; Protecting groups ; Amino acids ; Peptides ; Kinetics ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Investigations with Selective Deblocking Reagents for Adpoc-Protected Amino Acids and PeptidesSelective reagents for the removal of the Adpoc group have been developed. For this purpose several peptides containing tryptophan and N∊-Boc-lysine have been synthesized. Among several acidolytic reagents, 0.1 N HCl/TFEt/CHCl3 (1:9:1) and 50% HCOOH/TFEt/CHCl3 (1:9:1) show high selectivity especially for the N∊-tert-butyloxycarbonyl group of lysine. Cleavage rates are determined by HPLC and TLC.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/jlac.199319930124
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    A comparative investigation of the oxidation of silicon using H2/O2, TCA/O2 and HCl/O2 mixtures (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Advanced Materials for Optics and Electronics 2 (1993), S. 165-173 
    Details
    ISSN: 1057-9257
    Keywords: Thermal oxidation ; Kinetics ; Electrical properties ; Trichloroethane (TCA) ; Hydrogen chloride (HCl) ; Hydrogen/oxygen (H2/O2) ; VLSI ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: The oxidation of single-crystal silicon wafers has been investigated using an industrial thermal oxidation system. The growth characteristics and electrical properties of the oxides resulting from pure hydrogen/oxygen (H2/O2), trichloroethane/oxygen (TCA/O2) and hydrogen chlorid/oxygen (HCl/O2) mixtures have been investigated and compared. The addition of both HCl and TCA to oxygen produces higher growth rates and improved electrical characteristics. It is shown that the oxidation rate for TCA/O2 is approximately 30%-40% higher than for HCl/O2 and that comparable electrical properties can be readily obtained. A TCA/O2 ratio of 1 mol% gives the optimum process for VLSI applications, though 3 mol% HCl/O2 gives comparable results. It is suggested that the overall mechanisms governing the processes are similar. However, the TCA process is a safer and cleaner alternative because it generates HCl in situ in the oxidation chamber.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/amo.860020403
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    Sperm penetration through the zona pellucida of salt-stored hamster eggs is delayed (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 36 (1993), S. 328-330 
    Details
    ISSN: 1040-452X
    Keywords: Sperm capacitation ; Acrosome reaction ; Kinetics ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: One of the problems in assaying sperm capacitation is that live eggs mount a block to polyspermy at the zona pellucida. To circumvent this problem, researchers have started to use salt-stored eggs to assay sperm capacitation (Boatman et al., Gamete Res 19:19-29, 1988; Yoshimatsu et al., Gamete Res 21:115-126, 1988). These researchers have demonstrated that the zonae of salt-stored eggs were penetrable by capacitated sperm, but they did not examine whether the timing of penetration of fully capacitated sperm was altered. This report shows that zona penetration by fully capacitated sperm is delayed in both short-term salt-treated eggs (2 hr) and in eggs stored in salt for 〉2 days. These results indicate that the zona is modified when eggs are treated with a high-salt solution. © 1993 Wiley-Liss, Inc.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/mrd.1080360307
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    Substituenteneffekte auf die C-C-Bindungsstärke, 12[1]. Thermolysen aromatischer Pinakol-dimethylether zur Bestimmung der Stabilisierungsenergie von α-Methoxybenzyl-Radikalen[2] (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 1693-1699 
    Details
    ISSN: 0009-2940
    Keywords: C-C Bond homolysis ; Thermolysis ; Kinetics ; Radical stabilisation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Substituent Effects on the C-C Bond Strength, 12[1].-Thermolysis of Aromatic Pinacol Dimethyl Ethers and Stabilisation Energies of α-Methoxybenzyl Radicals[2]The phenyl-substituted pinacol dimethyl ethers meso- and DL- 5a-d have been prepared by reductive dimerisation of the dimethyl acetals 7a-d of the ketones 8a-d. 1H-NMR spectra and GC-retention times are used to distinguish between the diastereomers, and an X-ray structure analysis of meso-5a confirms these distinctive criteria. The products and the kinetics of the thermolysis reaction of 5a-d have been studied. A linear correlation between ΔG+ (300°C) of thermolysis and strain enthalpies Hs of 5, or its release Ds during the dissoziation into radicals 6, is observed. These correlations do not differ from those of the thermolysis of tetraalkyl-diphenylethanes (1, R=alkyl, S=phenyl)[3,20a]. Hence, the methoxy group does not influence the homolysis reaction of the C-C bond in 5compared to an alkyl group. It is concluded that any stabilisation of the radicals 6 by the alkoxy group[1] is canceled by an extra stabilisation of 5 by the geminal phenyl/methoxy pairs.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19931260728
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    Thermolabile Kohlenwasserstoffe, 32. Konkurrierende Cope-;Umlagerung und Homolyse von meso- und DL-3,4-Di(1-cyclohexen-1-yl)-2,2,5,5-tetramethylhexan (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 117-127 
    Details
    ISSN: 0009-2940
    Keywords: Radical stabilization, allylic ; Cope rearrangement ; C  -  C Bond cleavage ; Thermochemistry ; Kinetics ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermolabile Hydrocarbons, 32.  -  Competing Cope-;Rearrangement and Homolytic Decomposition of meso- and DL-3,4-Di(1-cyclohexen-1-yl)-2,2,5,5-tetramethylhexanemeso- and DL-3,4-di(1-cyclohexen-1-yl)-2,2,5,5-tetramethylhexane (3a) were prepared by an improved reduction procedure (Li/C2H5NH2) from meso- and DL-2,2,5,5-tetramethyl-3,4-diphenylhexane. Products of two competing thermal transformations, C  -  C cleavage vs. Cope rearrangement, were isolated and identified. From a kinetic analysis of this system of reactions, characteristic activation enthalpies and entropies were obtained for the competing transformations. The standard heat of formation of meso-3a (ΔHf0(g) = -58.4 ± 1.2 kcal/mol) was determined by combustion calorimetry and by measurement of its heat of sublimation. A strain enthalpy Hs (meso- 3a) = 10.2 ± 1.2 kcal/mol was derived therefrom. Force-field calculations of the diastereomers of 3a and the Cope products 8a were performed by using MM2, MM2ERW, and MM3 in order to analyse the conformational situation. The calculated ΔHf0(g) values for meso-3a are higher than the experimental value by 4.4 (MM2), 5.2 (MM2ERW), and 14.5 (MM3) kcal/mol. Obviously, the three computational methods require reliable parameters for highly branched olefins like 3a and 5a. From the experimental heat of formation ΔHt0(g) and strain enthalpy Hs of meso-3a and its ΔH* of homolysis the stabilization energy of the allylic radical 4 was determined to be 12.6 ± 1.5 kcal/mol.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19931260119
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    Defect Chemistry: Composition, Transport, and Reactions in the Solid State; Part II: KineticsPart I: Themodynamics appeared in the March issue of Angewandte Chemie [1].Dedicated to Professor Hermann Schmalzried on the occasion of his 60th birthday (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 32 (1993), S. 528-542 
    Details
    ISSN: 0570-0833
    Keywords: Defect chemistry ; Kinetics ; Solid-state reactions ; Semiconductors ; Heterogeneous catalysis ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Within the last few decades - though with its beginnings traceable to as early as 60 years ago - a direction of research has developed almost unnoticed by the classical chemical disciplines, such that one can now recognize a chemistry within the solid state that is analogous to the long-familiar chemistry in the liquid state. It arises from those departures from the ideal structure that are thermodynamically unavoidable, the point defects, and is referred to as defect chemistry. It includes the description of ionic and electronic effects, and it considers diffusion as a special step of the overall reaction. This area of chemistry enables one to describe and treat in a unified way many apparently widely different phenomena such as ionic conduction in crystals, doping effects and p-n junctions in semiconductors, color centers in alkali metal halides, image development in photography, passivation and corrosion of metals, the kinetics of the synthesis and sintering of solid materials, the problems of rock formation during the earth's evolution, the mechanisms of gas sensors and high temperature fuel cells, the performance of photosentive electrodes, variations of the electron balance in high temperature superconductors, elementary processes of heterogeneous catalysis, nonequilibrium transitions and oscillations in semiconductors in electric fields, and many more. In such phenomena the equilibrium concentration of defects has an important double role: it not only determines the disorder and the departures from the stoichiometric composition in the equilibrium state, but also, together with the mobility as the kinetic parameter, is the key parameter concerning the rates of physical processes, which are the main subject of the present discussion. Following the account of the thermodynamic fundamentals in Part I, this second part of the review will be concerned with kinetic processes. These are essentially the equilibration processes (physical diffusion, electrical conduction, chemical diffusion, and reactions) that take place under the influence of chemical and electric driving forces. As in Part I, here again the general characteristics of defect chemistry will clearly emerge, including the coexistence of ionic and electronic charge carriers, and the importance of the spatial coordinates. The concluding section will discuss some special characteristics of nonlinear processes that are too often overlooked in solid-state studies.
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    Role of intracellular calcium in NI-35-evoked collapse of neuronal growth cones (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-01-01
    Description: A myelin-associated protein from the central nervous system, the neurite growth inhibitor NI-35, inhibits regeneration of lesioned neuronal fiber tracts in vivo and growth of neurites in vitro. Growth cones of cultured rat dorsal root ganglion neurons arrested their growth and collapsed when exposed to liposomes containing NI-35. Before morphological changes, the concentration of free intracellular calcium ([Ca2+]i) showed a rapid and large increase in growth cones exposed to liposomes containing NI-35. Neither an increase in [Ca2+]i nor collapse of growth cones was detected in the presence of antibodies to NI-35. Dantrolene, an inhibitor of calcium release from caffeine-sensitive intracellular calcium stores, protected growth cones from collapse evoked by NI-35. Depletion of these caffeine-sensitive intracellular calcium stores prevented the increase in [Ca2+]i evoked by NI-35. The NI-35-evoked cascade of intracellular messengers that mediates collapse of growth cones includes the crucial step of calcium release from intracellular stores.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bandtlow, C E -- Schmidt, M F -- Hassinger, T D -- Schwab, M E -- Kater, S B -- NS24683/NS/NINDS NIH HHS/ -- NS28323/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1993 Jan 1;259(5091):80-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Brain Research Institute, University of Zurich, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8418499" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Caffeine/pharmacology ; Calcium/*metabolism ; Cells, Cultured ; Drug Carriers ; Fura-2 ; Ganglia, Spinal/*physiology ; Growth Inhibitors/*pharmacology ; Kinetics ; Liposomes ; Nerve Fibers/drug effects/*physiology/ultrastructure ; Neurons/drug effects/*physiology/ultrastructure ; Rats
    Print ISSN: 0036-8075
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    Rate and mechanism of nonhomologous recombination during a single cycle of retroviral replication (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-01-08
    Description: Oncogenes discovered in retroviruses such as Rous sarcoma virus were generated by transduction of cellular proto-oncogenes into the viral genome. Several different kinds of junctions between the viral and proto-oncogene sequences have been found in different viruses. A system of retrovirus vectors and a protocol that mimicked this transduction during a single cycle of retrovirus replication was developed. The transduction involved the formation of a chimeric viral-cellular RNA, strand switching of the reverse transcription growing point from an infectious retrovirus to the chimeric RNA, and often a subsequent deletion during the rest of viral DNA synthesis. A short region of sequence identity was frequently used for the strand switching. The rate of this process was about 0.1 to 1 percent of the rate of homologous retroviral recombination.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zhang, J -- Temin, H M -- CA-07175/CA/NCI NIH HHS/ -- CA-22443/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1993 Jan 8;259(5092):234-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉McArdle Laboratory for Cancer Research, University of Wisconsin-Madison 53706.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8421784" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Base Sequence ; *Cinnamates ; *DNA Replication ; DNA, Viral/chemistry/genetics ; Drug Resistance/genetics ; Genes, Viral ; Genetic Vectors ; Hygromycin B/analogs & derivatives ; Kinetics ; Mice ; Molecular Sequence Data ; Moloney murine leukemia virus/genetics ; Neomycin ; Plasmids ; *Proto-Oncogenes ; RNA, Viral/analysis/genetics ; *Recombination, Genetic ; Repetitive Sequences, Nucleic Acid ; Retroviridae/*genetics/physiology ; Transfection ; *Virus Replication
    Print ISSN: 0036-8075
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    Expression cloning and signaling properties of the rat glucagon receptor (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-03-12
    Description: Glucagon and the glucagon receptor are a primary source of control over blood glucose concentrations and are especially important to studies of diabetes in which the loss of control over blood glucose concentrations clinically defines the disease. A complementary DNA clone for the glucagon receptor was isolated by an expression cloning strategy, and the receptor protein was expressed in several kidney cell lines. The cloned receptor bound glucagon and caused an increase in the intracellular concentration of adenosine 3', 5'-monophosphate (cAMP). The cloned glucagon receptor also transduced a signal that led to an increased concentration of intracellular calcium. The glucagon receptor is similar to the calcitonin and parathyroid hormone receptors. It can transduce signals leading to the accumulation of two different second messengers, cAMP and calcium.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jelinek, L J -- Lok, S -- Rosenberg, G B -- Smith, R A -- Grant, F J -- Biggs, S -- Bensch, P A -- Kuijper, J L -- Sheppard, P O -- Sprecher, C A -- New York, N.Y. -- Science. 1993 Mar 12;259(5101):1614-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉ZymoGenetics Inc., Seattle, WA 98105.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8384375" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Calcium/pharmacology ; Cell Line ; Cloning, Molecular ; Cricetinae ; Cyclic AMP/metabolism ; Glucagon/metabolism/*pharmacology ; Kidney ; Kinetics ; Liver/*metabolism ; Molecular Sequence Data ; Rats ; Receptors, Gastrointestinal Hormone/genetics/metabolism/*physiology ; Receptors, Glucagon ; *Signal Transduction ; Transfection
    Print ISSN: 0036-8075
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    Formation of a molten globule intermediate early in the kinetic folding pathway of apomyoglobin (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-11-05
    Description: Hydrogen exchange pulse labeling and stopped-flow circular dichroism were used to establish that the structure of the earliest detectable intermediate formed during refolding of apomyoglobin corresponds closely to that of a previously characterized equilibrium molten globule. This compact, cooperatively folded intermediate was formed in less than 5 milliseconds and contained stable, hydrogen-bonded secondary structure localized in the A, G, and H helices and part of the B helix. The remainder of the B helix folded on a much slower time scale, followed by the C and E helices and the CD loop. The data indicate that a molten globule intermediate was formed on the kinetic folding pathway.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jennings, P A -- Wright, P E -- DK-34909/DK/NIDDK NIH HHS/ -- GM14541/GM/NIGMS NIH HHS/ -- RR04953/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 1993 Nov 5;262(5135):892-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Scripps Research Institute, La Jolla, California 92037.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8235610" target="_blank"〉PubMed〈/a〉
    Keywords: Apoproteins/*chemistry ; Circular Dichroism ; Hydrogen/chemistry ; Hydrogen Bonding ; Kinetics ; Magnetic Resonance Spectroscopy ; Models, Molecular ; Myoglobin/*chemistry ; *Protein Conformation ; *Protein Folding ; Protein Structure, Secondary
    Print ISSN: 0036-8075
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    Isolation of new ribozymes from a large pool of random sequences [see comment] (1993)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1993-09-10
    Description: An iterative in vitro selection procedure was used to isolate a new class of catalytic RNAs (ribozymes) from a large pool of random-sequence RNA molecules. These ribozymes ligate two RNA molecules that are aligned on a template by catalyzing the attack of a 3'-hydroxyl on an adjacent 5'-triphosphate--a reaction similar to that employed by the familiar protein enzymes that synthesize RNA. The corresponding uncatalyzed reaction also yields a 3',5'-phosphodiester bond. In vitro evolution of the population of new ribozymes led to improvement of the average ligation activity and the emergence of ribozymes with reaction rates 7 million times faster than the uncatalyzed reaction rate.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bartel, D P -- Szostak, J W -- New York, N.Y. -- Science. 1993 Sep 10;261(5127):1411-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Massachusetts General Hospital, Boston 02114.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7690155" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Biological Evolution ; Catalysis ; Kinetics ; Magnesium/metabolism ; Molecular Sequence Data ; Mutation ; Oligoribonucleotides/metabolism ; RNA/*metabolism ; RNA Ligase (ATP)/chemistry/isolation & purification/metabolism ; RNA, Catalytic/chemistry/*isolation & purification/metabolism ; Temperature ; Templates, Genetic
    Print ISSN: 0036-8075
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    Modal shifts in acetylcholine receptor channel gating confer subunit-dependent desensitization (1993)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1993-06-18
    Description: During the transition from embryonic to adult skeletal muscle, a decreased mean channel open time and accelerated desensitization of nicotinic acetylcholine (ACh) receptors result from the substitution of an epsilon subunit for gamma. A single ACh receptor channel of the embryonic type, expressed in Xenopus oocytes, interconverts between gating modes of short and long open time, whereas the adult receptor channel resides almost exclusively in the gating mode with short open time. Differences in the fraction of time spent in either gating mode account for the subunit dependence of both receptor open time and desensitization. Therefore, developmental changes in the kinetics of muscle ACh receptors may be imparted through subunit-dependent stabilization of intrinsic gating modes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Naranjo, D -- Brehm, P -- NS18205/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1993 Jun 18;260(5115):1811-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Neurobiology and Behavior, State University of New York, Stony Brook 11794.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8511590" target="_blank"〉PubMed〈/a〉
    Keywords: Acetylcholine/*pharmacology ; Animals ; Embryo, Nonmammalian ; *Ion Channel Gating ; Kinetics ; Oocytes ; Receptors, Cholinergic/*metabolism ; Xenopus
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    Requirement for a GTPase-activating protein in vesicle budding from the endoplasmic reticulum (1993)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1993-03-05
    Description: The binding and hydrolysis of guanosine triphosphate (GTP) by the small GTP-binding protein Sar1p is required to form transport vesicles from the endoplasmic reticulum (ER) in Saccharomyces cerevisiae. Experiments revealed that an interaction between Sar1p and the Sec23p subunit of an oligomeric protein is also required for vesicle budding. The isolated Sec23p subunit and the oligomeric complex stimulated guanosine triphosphatase (GTPase) activity of Sar1p 10- to 15-fold but did not activate two other small GTP-binding proteins involved in vesicle traffic (Ypt1p and ARF). Activation of GTPase was inhibited by an antibody to Sec23p but not by an antibody that inhibits the budding activity of the other subunit of the Sec23p complex. Also, activation was thermolabile in pure samples of Sec23p that were isolated from two independent sec23 mutant strains. It appears that Sec23p represents a new class of GTPase-activating protein because its sequence shows no similarity to any known member of this family.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Yoshihisa, T -- Barlowe, C -- Schekman, R -- New York, N.Y. -- Science. 1993 Mar 5;259(5100):1466-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California, Berkeley 94720.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8451644" target="_blank"〉PubMed〈/a〉
    Keywords: COP-Coated Vesicles ; Cloning, Molecular ; Endoplasmic Reticulum/*metabolism/ultrastructure ; Fungal Proteins/genetics/metabolism ; GTP-Binding Proteins/genetics/*metabolism ; GTPase-Activating Proteins ; Genes, Fungal ; Kinetics ; Macromolecular Substances ; *Monomeric GTP-Binding Proteins ; Mutagenesis ; Proteins/*metabolism ; Saccharomyces cerevisiae/genetics/*metabolism ; *Saccharomyces cerevisiae Proteins ; Spheroplasts/metabolism ; Vesicular Transport Proteins
    Print ISSN: 0036-8075
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    Probing the mechanism of staphylococcal nuclease with unnatural amino acids: kinetic and structural studies (1993)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1993-09-17
    Description: Staphylococcal nuclease is an enzyme with enormous catalytic power, accelerating phosphodiester bond hydrolysis by a factor of 10(16) over the spontaneous rate. The mechanistic basis for this rate acceleration was investigated by substitution of the active site residues Glu43, Arg35, and Arg87 with unnatural amino acid analogs. Two Glu43 mutants, one containing the nitro analog of glutamate and the other containing homoglutamate, retained high catalytic activity at pH 9.9, but were less active than the wild-type enzyme at lower pH values. The x-ray crystal structure of the homoglutamate mutant revealed that the carboxylate side chain of this residue occupies a position and orientation similar to that of Glu43 in the wild-type enzyme. The increase in steric bulk is accommodated by a backbone shift and altered torsion angles. The nitro and the homoglutamate mutants display similar pH versus rate profiles, which differ from that of the wild-type enzyme. Taken together, these studies suggest that Glu43 may not act as a general base, as previously thought, but may play a more complex structural role during catalysis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Judice, J K -- Gamble, T R -- Murphy, E C -- de Vos, A M -- Schultz, P G -- GM 14012-02S1/GM/NIGMS NIH HHS/ -- R01 GM49220/GM/NIGMS NIH HHS/ -- T32GM-08388/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1993 Sep 17;261(5128):1578-81.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of California, Berkeley 94720.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8103944" target="_blank"〉PubMed〈/a〉
    Keywords: 2-Aminoadipic Acid/chemistry ; Amino Acids/chemistry ; Aminobutyrates/chemistry ; Arginine/*chemistry ; Binding Sites ; Catalysis ; Glutamates/*chemistry ; Glutamic Acid ; Homocysteine/analogs & derivatives/chemistry ; Hydrogen Bonding ; Hydrogen-Ion Concentration ; Kinetics ; Micrococcal Nuclease/chemistry/genetics/*metabolism ; Mutation ; Plasmids ; X-Ray Diffraction
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    Mechanism-based inactivation of prostatic acid phosphatase (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-11-26
    Description: Protein phosphatases play important roles in the regulation of cell growth and metabolism, yet little is known about their enzymatic mechanism. By extrapolation from data on inhibitors of other types of hydrolases, an inhibitor of prostatic acid phosphatase was designed that is likely to function as a mechanism-based phosphotyrosine phosphatase inactivator. This molecule, 4-(fluoromethyl)phenyl phosphate, represents a useful paradigm for the design of potent and specific phosphatase inhibitors.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Myers, J K -- Widlanski, T S -- R01 GM47918-01/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1993 Nov 26;262(5138):1451-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Indiana University, Bloomington 47405.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8248785" target="_blank"〉PubMed〈/a〉
    Keywords: Acid Phosphatase/*antagonists & inhibitors/metabolism ; Alkylation ; Binding Sites ; Drug Design ; Humans ; Hydrolysis ; Kinetics ; Male ; Organophosphorus Compounds/metabolism/*pharmacology ; Prostate/*enzymology
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    Antagonism of catecholamine receptor signaling by expression of cytoplasmic domains of the receptors (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-03-05
    Description: The actions of many hormones and neurotransmitters are mediated by the members of a superfamily of receptors coupled to heterotrimeric guanine nucleotide-binding proteins (G proteins). These receptors are characterized by a highly conserved topographical arrangement in which seven transmembrane domains are connected by intracellular and extracellular loops. The interaction between these receptors and G proteins is mediated in large part by the third intracellular loop of the receptor. Coexpression of the third intracellular loop of the alpha 1B-adrenergic receptor with its parent receptor inhibited receptor-mediated activation of phospholipase C. The inhibition extended to the closely related alpha 1C-adrenergic receptor subtype, but not the phospholipase C-coupled M1 muscarinic acetylcholine receptor nor the adenylate cyclase-coupled D1A dopamine receptor. These results suggest that the receptor-G protein interface may represent a target for receptor antagonist drugs.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Luttrell, L M -- Ostrowski, J -- Cotecchia, S -- Kendall, H -- Lefkowitz, R J -- HL16037/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1993 Mar 5;259(5100):1453-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Medicine, Duke University Medical Center, Durham, NC 27710.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8383880" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Base Sequence ; Cell Line ; Cloning, Molecular ; Cyclic AMP/metabolism ; Cytoplasm/metabolism ; GTP-Binding Proteins/*metabolism ; Globins/genetics ; Glutathione Transferase/genetics/metabolism ; Humans ; Inositol Phosphates/metabolism ; Kinetics ; Molecular Sequence Data ; Muscarinic Antagonists ; Oligodeoxyribonucleotides ; Plasmids ; Protein Structure, Secondary ; Receptors, Adrenergic, alpha/genetics/*metabolism ; Receptors, Dopamine D1/antagonists & inhibitors/genetics/*metabolism ; Receptors, Muscarinic/genetics/*metabolism ; Recombinant Fusion Proteins/metabolism ; *Signal Transduction ; Transfection ; Type C Phospholipases/metabolism
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    Converting tissue plasminogen activator to a zymogen: a regulatory triad of Asp-His-Ser (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-10-15
    Description: Unlike most serine proteases of the chymotrypsin family, tissue-type plasminogen activator (tPA) is secreted from cells as an active, single-chain enzyme with a catalytic efficiency only slightly lower than that of the proteolytically cleaved form. A zymogenic mutant of tPA has been engineered that displays a reduction in catalytic efficiency by a factor of 141 in the single-chain form while retaining full activity in the cleaved form. The residues introduced in the mutant, serine 292 and histidine 305, are proposed to form a hydrogen-bonded network with aspartate 477, similar to the aspartate 194-histidine 40-serine 32 network found to stabilize the zymogen chymotrypsinogen.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Madison, E L -- Kobe, A -- Gething, M J -- Sambrook, J F -- Goldsmith, E J -- New York, N.Y. -- Science. 1993 Oct 15;262(5132):419-21.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas 75235.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8211162" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Aspartic Acid/chemistry ; Base Sequence ; Catalysis ; Chymotrypsin/chemistry/metabolism ; Enzyme Precursors/chemistry/*metabolism ; Histidine/chemistry ; Hydrogen Bonding ; Kinetics ; Molecular Sequence Data ; Mutagenesis, Site-Directed ; Mutation ; Plasminogen/metabolism ; Plasminogen Activator Inhibitor 1/metabolism ; Serine/chemistry ; Tissue Plasminogen Activator/chemistry/genetics/*metabolism
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    Separate GTP binding and GTPase activating domains of a G alpha subunit (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-12-17
    Description: Most members of the guanosine triphosphatase (GTPase) superfamily hydrolyze guanosine triphosphate (GTP) quite slowly unless stimulated by a GTPase activating protein or GAP. The alpha subunits (G alpha) of the heterotrimeric G proteins hydrolyze GTP much more rapidly and contain an approximately 120-residue insert not found in other GTPases. Interactions between a G alpha insert domain and a G alpha GTP-binding core domain, both expressed as recombinant proteins, show that the insert acts biochemically as a GAP. The results suggest a general mechanism for GAP-dependent hydrolysis of GTP by other GTPases.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Markby, D W -- Onrust, R -- Bourne, H R -- 5F32-GM13918/GM/NIGMS NIH HHS/ -- CA54427/CA/NCI NIH HHS/ -- GM27800/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1993 Dec 17;262(5141):1895-901.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pharmcology, University of California, San Francisco 94143.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8266082" target="_blank"〉PubMed〈/a〉
    Keywords: Adenylyl Cyclases/metabolism ; Amino Acid Sequence ; Animals ; Cell Line ; Colforsin/pharmacology ; Cyclic AMP/metabolism ; GTP Phosphohydrolases/*metabolism ; GTP-Binding Proteins/chemistry/*metabolism ; Guanosine 5'-O-(3-Thiotriphosphate)/metabolism/pharmacology ; Guanosine Triphosphate/*metabolism ; Hydrolysis ; Kinetics ; Molecular Sequence Data ; Mutation ; Protein Conformation
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    Kinetics of folding of the all-beta sheet protein interleukin-1 beta (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-05-21
    Description: The folding of the all-beta sheet protein, interleukin-1 beta, was studied with nuclear magnetic resonance (NMR) spectroscopy, circular dichroism, and fluorescence. Ninety percent of the beta structure present in the native protein, as monitored by far-ultraviolet circular dichroism, was attained within 25 milliseconds, correlating with the first kinetic phase determined by tryptophan and 1-anilinonaphthalene-8-sulfonate fluorescence. In contrast, formation of stable native secondary structure, as measured by quenched-flow deuterium-hydrogen exchange experiments, began after only 1 second. Results from the NMR experiments indicated the formation of at least two intermediates with half-lives of 0.7 to 1.5 and 15 to 25 seconds. The final stabilization of the secondary structure, however, occurs on a time scale much greater than 25 seconds. These results differ from previous results on mixed alpha helix-beta sheet proteins in which both the alpha helices and beta sheets were stabilized very rapidly (less than 10 to 20 milliseconds).〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Varley, P -- Gronenborn, A M -- Christensen, H -- Wingfield, P T -- Pain, R H -- Clore, G M -- New York, N.Y. -- Science. 1993 May 21;260(5111):1110-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (NIH), Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8493553" target="_blank"〉PubMed〈/a〉
    Keywords: Circular Dichroism ; Hydrogen Bonding ; Interleukin-1/*chemistry ; Kinetics ; Magnetic Resonance Spectroscopy ; Protein Conformation ; Protein Folding ; Protein Structure, Secondary ; Protein Structure, Tertiary ; Spectrometry, Fluorescence
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    Arrestin function in inactivation of G protein-coupled receptor rhodopsin in vivo (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-06-25
    Description: Arrestins have been implicated in the regulation of many G protein-coupled receptor signaling cascades. Mutations in two Drosophila photoreceptor-specific arrestin genes, arrestin 1 and arrestin 2, were generated. Analysis of the light response in these mutants shows that the Arr1 and Arr2 proteins are mediators of rhodopsin inactivation and are essential for the termination of the phototransduction cascade in vivo. The saturation of arrestin function by an excess of activated rhodopsin is responsible for a continuously activated state of the photoreceptors known as the prolonged depolarized afterpotential. In the absence of arrestins, photoreceptors undergo light-dependent retinal degeneration as a result of the continued activity of the phototransduction cascade. These results demonstrate the fundamental requirement for members of the arrestin protein family in the regulation of G protein-coupled receptors and signaling cascades in vivo.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Dolph, P J -- Ranganathan, R -- Colley, N J -- Hardy, R W -- Socolich, M -- Zuker, C S -- R01 EY008768/EY/NEI NIH HHS/ -- New York, N.Y. -- Science. 1993 Jun 25;260(5116):1910-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, La Jolla, CA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8316831" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Animals, Genetically Modified ; *Arrestins ; Drosophila ; Drosophila Proteins ; Eye Proteins/genetics/*physiology ; Female ; GTP-Binding Proteins/*metabolism ; Genes, Insect ; Kinetics ; Male ; Molecular Sequence Data ; Mutation ; Phosphoproteins/genetics/*physiology ; Photic Stimulation ; Photoreceptor Cells/cytology/*physiology ; Rhodopsin/analogs & derivatives/*metabolism
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    Antibody catalysis of a disfavored chemical transformation (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-01-22
    Description: Organic reactions are often limited by stereoelectronic constrains that appear along the reaction coordinate. An antibody has been generated that overcomes these constraints and catalyzes a highly disfavored chemical transformation. The antibody facilitates the difficult 6-endo-tet ring closure of an epoxy-alcohol to form a tetrahydropyran. The catalyzed process is in formal violation of what has become known as Baldwin's rules for ring-closure reactions. In addition to controlling the regiochemistry of the disfavored cyclization reaction, these catalytic antibodies resolve enantiomeric substrates to afford a stereochemically pure product. The principles demonstrated in this study may be applicable to other disfavored chemical processes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Janda, K D -- Shevlin, C G -- Lerner, R A -- New York, N.Y. -- Science. 1993 Jan 22;259(5094):490-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Scripps Research Institute, La Jolla, CA 92037.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8424171" target="_blank"〉PubMed〈/a〉
    Keywords: Antibodies/*metabolism ; Catalysis ; Enzymes/metabolism ; Heterocyclic Compounds/*chemistry ; Indicators and Reagents ; Isomerism ; Kinetics
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    Catalysis: design versus selection (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-09-10
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Benner, S A -- New York, N.Y. -- Science. 1993 Sep 10;261(5127):1402-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory for Organic Chemistry, Eidgenossisiche Technische Hochschule Zentrum, Zurich, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8367723" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; DNA-Directed RNA Polymerases/metabolism ; Kinetics ; RNA Ligase (ATP)/chemistry/metabolism ; RNA, Catalytic/chemistry/*metabolism
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    CNTF protection of oligodendrocytes against natural and tumor necrosis factor-induced death (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-01-29
    Description: A proportion of developing oligodendrocytes undergo natural cell death by apoptosis, and mature oligodendrocytes die, either by apoptosis or necrosis, in response to injurious signals such as cytotoxic cytokines and complement. Ciliary neurotrophic factor (CNTF), a trophic factor found in astrocytes in the central nervous system (CNS), promoted the survival and maturation of cultured oligodendrocytes. This trophic factor also protected oligodendrocytes from death induced by tumor necrosis factors (apoptosis) but not against complement (necrosis). These results suggest that CNTF functions in the survival of oligodendrocytes during development and may lead to therapeutic approaches for degenerative diseases of the CNS that involve oligodendrocyte destruction.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Louis, J C -- Magal, E -- Takayama, S -- Varon, S -- NS16349/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1993 Jan 29;259(5095):689-92.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, University of California, San Diego, La Jolla 92093.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8430320" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Astrocytes/physiology ; Cell Death/*drug effects ; Cell Survival/drug effects ; Cells, Cultured ; Central Nervous System/physiology ; Ciliary Neurotrophic Factor ; Dose-Response Relationship, Drug ; Humans ; Kinetics ; Lymphotoxin-alpha/*pharmacology ; Nerve Growth Factors/*pharmacology ; Nerve Tissue Proteins/*pharmacology ; Oligodendroglia/cytology/drug effects/*physiology ; Recombinant Proteins/pharmacology ; Time Factors ; Tumor Necrosis Factor-alpha/*pharmacology
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    Protein enhancement of hammerhead ribozyme catalysis (1993)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1993-10-01
    Description: When the recognition sequence of a ribozyme is extended beyond a certain length, turnover is slowed and specificity is decreased. Here, it is shown that a protein can help a ribozyme overcome these general limitations on ribozyme activity. Cleavage of an RNA oligonucleotide by a hammerhead ribozyme is enhanced 10- to 20-fold upon addition of a protein derived from the p7 nucleocapsid (NC) protein of human immunodeficiency virus-type 1. The NC protein also enhances the ability of the ribozyme to discriminate between cleavage of RNA oligonucleotides with differing sequences. These catalytic improvements can be attributed to the strand exchange activity of this RNA binding protein. It is conceivable that endogenous or added proteins may provide analogous increases in ribozyme activity and specificity in vivo.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tsuchihashi, Z -- Khosla, M -- Herschlag, D -- New York, N.Y. -- Science. 1993 Oct 1;262(5130):99-102.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Stanford University, CA 94305.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7692597" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; *Capsid Proteins ; Catalysis ; DNA, Single-Stranded/metabolism ; Gene Products, gag/*metabolism ; Kinetics ; Molecular Sequence Data ; Oligoribonucleotides/*metabolism ; RNA/*metabolism ; RNA, Catalytic/chemistry/*metabolism ; Substrate Specificity ; *Viral Proteins ; Zinc Fingers ; gag Gene Products, Human Immunodeficiency Virus
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    Role of the acylated amino terminus of recoverin in Ca(2+)-dependent membrane interaction (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-02-05
    Description: Recoverin, a calcium ion (Ca2+)-binding protein of vertebrate photoreceptors, binds to photoreceptor membranes when the Ca2+ concentration is greater than 1 micromolar. This interaction requires a fatty acyl residue covalently linked to the recoverin amino (NH2)-terminus. Removal of the acyl residue, either by proteolytic cleavage of the NH2-terminus or by production of nonacylated recoverin, prevented recoverin from binding to membranes. The acylated recoverin NH2-terminus could be cleaved by trypsin only when Ca2+ was bound to recoverin. These results suggest that the hydrophobic NH2-terminus is constrained in Ca(2+)-free recoverin and liberated by Ca2+ binding. The hydrophobic acyl moiety of recoverin may interact with the membrane only when recoverin binds Ca2+.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Dizhoor, A M -- Chen, C K -- Olshevskaya, E -- Sinelnikova, V V -- Phillipov, P -- Hurley, J B -- EYO6641/EY/NEI NIH HHS/ -- New York, N.Y. -- Science. 1993 Feb 5;259(5096):829-32.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of Washington, Seattle 98195.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8430337" target="_blank"〉PubMed〈/a〉
    Keywords: 1,2-Dipalmitoylphosphatidylcholine ; Acylation ; Animals ; Antigens, Neoplasm/isolation & purification/*metabolism ; Calcium/*metabolism/pharmacology ; Calcium-Binding Proteins/isolation & purification/*metabolism ; Cattle ; Cell Membrane/metabolism ; Egtazic Acid/pharmacology ; Electrophoresis, Polyacrylamide Gel ; *Eye Proteins ; Hippocalcin ; Kinetics ; *Lipoproteins ; Liposomes ; Membrane Proteins/isolation & purification/*metabolism ; Molecular Weight ; Myristic Acid ; Myristic Acids/*metabolism ; *Nerve Tissue Proteins ; Peptide Fragments/isolation & purification ; Phosphatidylserines ; Protein Binding ; Recoverin ; Rod Cell Outer Segment/*metabolism
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    Synthesis and degradation of cyclic ADP-ribose by NAD glycohydrolases (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-09-03
    Description: Cyclic adenosine diphosphoribose (cADPR), a recently discovered metabolite of nicotinamide adenine dinucleotide (NAD), is a potent calcium-releasing agent postulated to be a new second messenger. An enzyme that catalyzes the synthesis of cADPR from NAD and the hydrolysis of cADPR to ADP-ribose (ADPR) was purified to homogeneity from canine spleen microsomes. The net conversion of NAD to ADPR categorizes this enzyme as an NAD glycohydrolase. NAD glycohydrolases are ubiquitous membrane-bound enzymes that have been known for many years but whose function has not been identified. The results presented here suggest that these enzymes may function in the regulation of calcium homeostasis by the ability to synthesize and degrade cADPR.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kim, H -- Jacobson, E L -- Jacobson, M K -- CA43894/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1993 Sep 3;261(5126):1330-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Molecular Biology, University of North Texas Health Science Center at Fort Worth 76107.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8395705" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Diphosphate Ribose/*analogs & derivatives/biosynthesis/metabolism ; Animals ; Calcium/metabolism ; Cyclic ADP-Ribose ; Dogs ; Hydrolysis ; Kinetics ; NAD/metabolism ; NAD+ Nucleosidase/isolation & purification/*metabolism ; Spleen/enzymology
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    Activation of the sphingomyelin signaling pathway in intact EL4 cells and in a cell-free system by IL-1 beta (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-01-22
    Description: The mechanism of interleukin-1 (IL-1) signaling is unknown. Tumor necrosis factor-alpha uses a signal transduction pathway that involves sphingomyelin hydrolysis to ceramide and stimulation of a ceramide-activated protein kinase. In intact EL4 thymoma cells, IL-1 beta similarly stimulated a rapid decrease of sphingomyelin and an elevation of ceramide, and enhanced ceramide-activated protein kinase activity. This cascade was also activated by IL-1 beta in a cell-free system, demonstrating tight coupling to the receptor. Exogenous sphingomyelinase, but not phospholipases A2, C, or D, in combination with phorbol ester replaced IL-1 beta to stimulate IL-2 secretion. Thus, IL-1 beta signals through the sphingomyelin pathway.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Mathias, S -- Younes, A -- Kan, C C -- Orlow, I -- Joseph, C -- Kolesnick, R N -- R0-1-CA-42385/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1993 Jan 22;259(5094):519-22.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Signal Transduction, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10021.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8424175" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Cell-Free System ; Ceramides/*metabolism ; Dose-Response Relationship, Drug ; Interleukin-1/*pharmacology ; Interleukin-2/biosynthesis ; Kinetics ; Mice ; Molecular Sequence Data ; Protein Kinases/metabolism ; Signal Transduction/*drug effects ; Sphingomyelin Phosphodiesterase/pharmacology ; Sphingomyelins/*metabolism ; Substrate Specificity ; Thymoma ; Thymus Neoplasms ; Tumor Cells, Cultured ; Type C Phospholipases/pharmacology
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    Phosphorylation and modulation of a kainate receptor (GluR6) by cAMP-dependent protein kinase (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-02-19
    Description: Ligand-gated ion channels gated by glutamate constitute the major excitatory neurotransmitter system in the mammalian brain. The functional modulation of GluR6, a kainate-activated glutamate receptor, by adenosine 3',5'-monophosphate-dependent protein kinase A (PKA) was examined with receptors expressed in human embryonic kidney cells. Kainate-evoked currents underwent a rapid desensitization that was blocked by lectins. Kainate currents were potentiated by intracellular perfusion of PKA, and this potentiation was blocked by co-application of an inhibitory peptide. Site-directed mutagenesis was used to identify the site or sites of phosphorylation on GluR6. Although mutagenesis of two serine residues, Ser684 and Ser666, was required for complete abolition of the PKA-induced potentiation, Ser684 may be the preferred site of phosphorylation in native GluR6 receptor complexes. These results indicate that glutamate receptor function can be directly modulated by protein phosphorylation and suggest that a dynamic regulation of excitatory receptors could be associated with some forms of learning and memory in the mammalian brain.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wang, L Y -- Taverna, F A -- Huang, X P -- MacDonald, J F -- Hampson, D R -- New York, N.Y. -- Science. 1993 Feb 19;259(5098):1173-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology, University of Toronto, Ontario, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8382377" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Base Sequence ; Binding Sites ; Brain/*physiology ; Cells, Cultured ; Concanavalin A/pharmacology ; Evoked Potentials/drug effects ; Humans ; Kainic Acid/*pharmacology ; Kidney ; Kinetics ; Membrane Potentials/drug effects ; Molecular Sequence Data ; Mutagenesis, Site-Directed ; Oligodeoxyribonucleotides ; Protein Kinases/*metabolism ; Receptors, Glutamate/drug effects/genetics/*physiology ; Receptors, Kainic Acid ; Serine ; Wheat Germ Agglutinins/pharmacology
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    Substrate phage: selection of protease substrates by monovalent phage display (1993)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1993-05-21
    Description: A method is described here for identifying good protease substrates among approximately 10(7) possible sequences. A library of fusion proteins was constructed containing an amino-terminal domain used to bind to an affinity support, followed by a randomized protease substrate sequence and the carboxyl-terminal domain of M13 gene III. Each fusion protein was displayed as a single copy on filamentous phagemid particles (substrate phage). Phage were then bound to an affinity support and treated with the protease of interest. Phage with good protease substrates were released, whereas phage with substrates that resisted proteolysis remained bound. After several rounds of binding, proteolysis, and phagemid propagation, sensitive and resistant substrate sequences were identified for two different proteases, a variant of subtilisin and factor Xa. The technique may also be useful for studying the sequence specificity of a variety of posttranslational modifications.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Matthews, D J -- Wells, J A -- New York, N.Y. -- Science. 1993 May 21;260(5111):1113-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Protein Engineering, Genentech, South San Francisco, CA 94080.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8493554" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Bacteriophages/*genetics ; Base Sequence ; Computer Simulation ; Factor Xa/chemistry/*metabolism ; Genetic Vectors ; Humans ; Kinetics ; Models, Molecular ; Molecular Sequence Data ; Mutagenesis, Site-Directed ; Oligopeptides/chemistry/*metabolism ; Recombinant Fusion Proteins/chemistry/metabolism ; Substrate Specificity ; Subtilisins/chemistry/genetics/*metabolism
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    Colicin E1 binding to membranes: time-resolved studies of spin-labeled mutants (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-02-12
    Description: To investigate the mechanism of interaction of the toxin colicin E1 with membranes, three cysteine substitution mutants and the wild type of the channel-forming fragment were spin labeled at the unique thiol. Time-resolved interaction of these labeled proteins with phospholipid vesicles was investigated with stopped-flow electron paramagnetic resonance spectroscopy. The fragment interacts with neutral bilayers at low pH, indicating that the interaction is hydrophobic rather than electrostatic. The interaction occurs in at least two distinct steps: (i) rapid adsorption to the surface; and (ii) slow, rate-limiting insertion of the hydrophobic central helices into the membrane interior.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shin, Y K -- Levinthal, C -- Levinthal, F -- Hubbell, W L -- EY05216/EY/NEI NIH HHS/ -- New York, N.Y. -- Science. 1993 Feb 12;259(5097):960-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Jules Stein Eye Institute, University of California, Los Angeles 90024.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8382373" target="_blank"〉PubMed〈/a〉
    Keywords: Adsorption ; Binding Sites ; Cell Membrane/*metabolism ; Colicins/chemistry/genetics/*metabolism ; Cysteine/genetics ; Electron Spin Resonance Spectroscopy ; Hydrogen-Ion Concentration ; Kinetics ; Lipid Bilayers/metabolism ; *Mutagenesis ; Peptide Fragments/metabolism ; Protein Structure, Secondary ; *Spin Labels
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    Altered prevalence of gating modes in neurotransmitter inhibition of N-type calcium channels (1993)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1993-02-12
    Description: G protein-mediated inhibition of voltage-activated calcium channels by neurotransmitters has important consequences for the control of synaptic strength. Single-channel recordings of N-type calcium channels in frog sympathetic neurons reveal at least three distinct patterns of gating, designated low-Po, medium-Po, and high-Po modes according to their probability of being open (Po) at -10 millivolts. The high-Po mode is responsible for the bulk of divalent cation entry in the absence of neurotransmitter. Norepinephrine greatly decreased the prevalence of high-Po gating and increased the proportion of time a channel exhibited low-Po behavior or no activity at all, which thereby reduced the overall current. Directly observed patterns of transition between the various modes suggest that activated G protein alters the balance between modal behaviors that freely interconvert even in the absence of modulatory signaling.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Delcour, A H -- Tsien, R W -- HL13156/HL/NHLBI NIH HHS/ -- NS24607/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1993 Feb 12;259(5097):980-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular and Cellular Physiology, Beckman Center, Stanford University Medical Center, CA 94305.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8094902" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Anura ; Calcium Channels/*drug effects/*physiology ; Cations, Divalent ; Electric Stimulation ; Electrophysiology ; GTP-Binding Proteins/physiology ; Ion Channel Gating/*physiology ; Kinetics ; Neurons/physiology ; Neurotransmitter Agents/*pharmacology ; Norepinephrine/pharmacology ; Sympathetic Nervous System/cytology/physiology ; Synapses/physiology
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    Betacellulin: a mitogen from pancreatic beta cell tumors (1993)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1993-03-12
    Description: Betacellulin, a member of the epidermal growth factor family, has been identified in the conditioned medium of cell lines derived from mouse pancreatic beta cell tumors. Betacellulin is a 32-kilodalton glycoprotein that appears to be processed from a larger transmembrane precursor by proteolytic cleavage. The carboxyl-terminal domain of betacellulin has 50 percent sequence similarity with that of rat transforming growth factor alpha. Betacellulin is a potent mitogen for retinal pigment epithelial cells and vascular smooth muscle cells.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shing, Y -- Christofori, G -- Hanahan, D -- Ono, Y -- Sasada, R -- Igarashi, K -- Folkman, J -- CA 70118/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1993 Mar 12;259(5101):1604-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Surgery, Children's Hospital, Boston, MA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8456283" target="_blank"〉PubMed〈/a〉
    Keywords: 3T3 Cells ; Amino Acid Sequence ; Animals ; Base Sequence ; Betacellulin ; Cell Division/drug effects ; Cells, Cultured ; DNA Replication/drug effects ; Endothelium, Vascular/cytology/drug effects ; Epidermal Growth Factor/pharmacology ; Growth Substances/*genetics/isolation & purification/pharmacology ; Humans ; *Intercellular Signaling Peptides and Proteins ; Islets of Langerhans/physiopathology ; Kinetics ; Mice ; Molecular Sequence Data ; Muscle, Smooth, Vascular/cytology/drug effects ; Oligodeoxyribonucleotides ; Pancreatic Neoplasms/*physiopathology ; Pigment Epithelium of Eye/cytology/drug effects ; Polymerase Chain Reaction/methods ; Protein Precursors/genetics ; Rats ; Receptor, Epidermal Growth Factor/metabolism ; Recombinant Proteins/pharmacology ; Sequence Homology, Amino Acid ; Thymidine/metabolism ; Transforming Growth Factor alpha/genetics
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    Phosphorodithioate DNA as a potential therapeutic drug (1993)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1993-03-12
    Description: This article summarizes methods for the synthesis of phosphorodithioate-linked deoxyoligonucleotides and details an analysis of one of the distinctive properties of phosphorodithioate DNA oligomers, their ability to strongly inhibit human immunodeficiency virus type-1 reverse transcriptase (HIV-1 RT). Mechanistic studies indicate that oligomers of this type interfere with enzyme function by binding tightly to the active site for primer-template, which results in low or subnanomolar inhibitory constants. Although many of these studies have used deoxyoligocytidine analogs, a rationally designed approach has led to the discovery of a very active phosphorodithioate deoxyoligonucleotide inhibitor. This type of inhibitor, which binds strongly to the primer-template active site of HIV-1 RT, provides another type of potential therapeutic agent against HIV-1.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Marshall, W S -- Caruthers, M H -- GM21120/GM/NIGMS NIH HHS/ -- GM25680/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1993 Mar 12;259(5101):1564-70.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry and Biochemistry, University of Colorado, Boulder 80309.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7681216" target="_blank"〉PubMed〈/a〉
    Keywords: Antiviral Agents/*chemical synthesis/pharmacology ; Base Sequence ; HIV Reverse Transcriptase ; HIV-1/drug effects/*enzymology ; Kinetics ; Molecular Sequence Data ; Oligodeoxyribonucleotides/*chemical synthesis/pharmacology ; Organothiophosphates/*chemical synthesis/pharmacology ; *Reverse Transcriptase Inhibitors ; Structure-Activity Relationship
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    Multiple RNA polymerase conformations and GreA: control of the fidelity of transcription (1993)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1993-11-05
    Description: Pre-steady state kinetics of misincorporation were used to investigate the addition of single nucleotides to nascent RNA by Escherichia coli RNA polymerase during transcription elongation. The results were fit with a branched kinetic mechanism that permits conformational switching, at each template position, between an activated and an unactivated enzyme complex, both of which can bind nucleotide triphosphates (NTPs) from solution. The complex exists most often in the long-lived activated state, and only becomes unactivated when transcription is slowed. This model permits multiple levels of nucleotide discrimination in transcription, since the complex can be "kinetically trapped" in the unactivated state in the absence of the correct NTP or if the 3' terminal residue is incorrectly matched. The transcription cleavage factor GreA (or an activity enhanced by GreA) increased the fidelity of transcription by preferential cleavage of transcripts containing misincorporated residues in the unactivated state of the elongation complex. This cleavage mechanism by GreA may prevent the formation of "dead-end" transcription complexes in vivo.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Erie, D A -- Hajiseyedjavadi, O -- Young, M C -- von Hippel, P H -- GM-12915/GM/NIGMS NIH HHS/ -- GM-15792/GM/NIGMS NIH HHS/ -- GM-29158/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1993 Nov 5;262(5135):867-73.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute of Molecular Biology, University of Oregon, Eugene 97403.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8235608" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; DNA-Directed RNA Polymerases/*chemistry/metabolism ; Endoribonucleases/metabolism ; Escherichia coli/enzymology ; *Escherichia coli Proteins ; Kinetics ; Models, Genetic ; Molecular Sequence Data ; Nucleotides/metabolism ; Peptide Elongation Factors/*metabolism ; Protein Conformation ; RNA, Messenger/*biosynthesis/metabolism ; Templates, Genetic ; Transcription Factors/*metabolism ; *Transcription, Genetic ; Uridine Triphosphate/metabolism
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    SH2-containing phosphotyrosine phosphatase as a target of protein-tyrosine kinases (1993)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1993-03-12
    Description: A mouse phosphotyrosine phosphatase containing two Src homology 2 (SH2) domains, Syp, was identified. Syp bound to autophosphorylated epidermal growth factor (EGF) and platelet-derived growth factor (PDGF) receptors through its SH2 domains and was rapidly phosphorylated on tyrosine in PDGF- and EGF-stimulated cells. Furthermore, Syp was constitutively phosphorylated on tyrosine in cells transformed by v-src. This mammalian phosphatase is most closely related, especially in its SH2 domains, to the corkscrew (csw) gene product of Drosophila, which is required for signal transduction downstream of the Torso receptor tyrosine kinase. The Syp gene is widely expressed throughout embryonic mouse development and in adult tissues. Thus, Syp may function in mammalian embryonic development and as a common target of both receptor and nonreceptor tyrosine kinases.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Feng, G S -- Hui, C C -- Pawson, T -- New York, N.Y. -- Science. 1993 Mar 12;259(5101):1607-11.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Molecular and Developmental Biology, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8096088" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Base Sequence ; Cell Line, Transformed ; Cell Transformation, Neoplastic ; Embryo, Mammalian ; Embryonic and Fetal Development ; Epidermal Growth Factor/pharmacology ; *Genes, src ; Humans ; Intracellular Signaling Peptides and Proteins ; Kinetics ; Mice ; Molecular Sequence Data ; Oligodeoxyribonucleotides ; Phosphorylation ; Platelet-Derived Growth Factor/pharmacology ; Poly A/isolation & purification/metabolism ; Polymerase Chain Reaction ; Protein Tyrosine Phosphatase, Non-Receptor Type 11 ; Protein Tyrosine Phosphatase, Non-Receptor Type 6 ; Protein Tyrosine Phosphatases/genetics/*metabolism ; Protein-Tyrosine Kinases/*metabolism ; RNA, Messenger/isolation & purification/metabolism ; Rats ; Receptor, Epidermal Growth Factor/metabolism ; Receptors, Platelet-Derived Growth Factor/genetics/metabolism ; Sequence Homology, Amino Acid ; Transfection
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    A functional role for GTP-binding proteins in synaptic vesicle cycling (1993)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1993-02-19
    Description: The squid giant synapse was used to test the hypothesis that guanosine-5'-triphosphate (GTP)-binding proteins regulate the local distribution of synaptic vesicles within nerve terminals. Presynaptic injection of the nonhydrolyzable GTP analog GTP gamma S irreversibly inhibited neurotransmitter release without changing either the size of the calcium signals produced by presynaptic action potentials or the number of synaptic vesicles docked at presynaptic active zones. Neurotransmitter release was also inhibited by injection of the nonhydrolyzable guanosine diphosphate (GDP) analog GDP beta S but not by injection of AIF4-. These results suggest that a small molecular weight GTP-binding protein directs the docking of synaptic vesicles that occurs before calcium-dependent neurotransmitter release. Depletion of undocked synaptic vesicles by GTP gamma S indicates that additional GTP-binding proteins function in the terminal at other steps responsible for synaptic vesicle replenishment.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hess, S D -- Doroshenko, P A -- Augustine, G J -- NS-21624/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1993 Feb 19;259(5098):1169-72.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Sciences, University of Southern California.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8438167" target="_blank"〉PubMed〈/a〉
    Keywords: Aluminum/pharmacology ; *Aluminum Compounds ; Animals ; Calcium/metabolism ; Decapodiformes ; *Fluorides ; Fluorine/pharmacology ; GTP-Binding Proteins/*physiology ; Ganglia/physiology ; Guanosine 5'-O-(3-Thiotriphosphate)/pharmacology ; Guanosine Diphosphate/analogs & derivatives/metabolism/pharmacology ; Guanosine Triphosphate/metabolism ; In Vitro Techniques ; Kinetics ; Models, Neurological ; Nerve Endings/physiology/ultrastructure ; Signal Transduction/drug effects ; Synaptic Vesicles/drug effects/*physiology/ultrastructure ; Thionucleotides/pharmacology ; Time Factors
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    An inhibitor of p34CDC28 protein kinase activity from Saccharomyces cerevisiae (1993)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1993-01-08
    Description: The p34CDC28 protein from Saccharomyces cerevisiae is a homolog of the p34cdc2 protein kinase, a fundamental regulator of cell division in all eukaryotic cells. Once activated it initiates the visible events of mitosis (chromosome condensation, nuclear envelope breakdown, and spindle formation). The p34CDC28 protein also has a critical role in the initiation of DNA synthesis. The protein kinase activity is regulated by cycles of phosphorylation and dephosphorylation and by periodic association with cyclins. An endogenous 40-kilodalton protein (p40) originally identified as a substrate of the p34CDC28 protein kinase was purified. The p40 protein bound tightly to p34CDC28 and inhibited the activity of the kinase. The p40 protein may provide another mechanism to regulate p34CDC28 protein kinase activity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Mendenhall, M D -- New York, N.Y. -- Science. 1993 Jan 8;259(5092):216-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of Kentucky, Lexington 40536.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8421781" target="_blank"〉PubMed〈/a〉
    Keywords: CDC28 Protein Kinase, S cerevisiae ; Cyclins/metabolism ; Histones/metabolism ; Kinetics ; Molecular Weight ; Phosphorylation ; Phosphothreonine/metabolism ; *Protein Kinase Inhibitors ; Protein Kinases/metabolism ; Saccharomyces cerevisiae/*enzymology
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    Identification of a ten-amino acid proline-rich SH3 binding site (1993)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1993-02-19
    Description: The Src homology 3 (SH3) region is a small protein domain present in a very large group of proteins, including cytoskeletal elements and signaling proteins. It is believed that SH3 domains serve as modules that mediate protein-protein associations and, along with Src homology 2 (SH2) domains, regulate cytoplasmic signaling. The SH3 binding sites of two SH3 binding proteins were localized to a nine- or ten-amino acid stretch very rich in proline residues. Similar SH3 binding motifs exist in the formins, proteins that function in pattern formation in embryonic limbs of the mouse, and one subtype of the muscarinic acetylcholine receptor. Identification of the SH3 binding site provides a basis for understanding the interaction between the SH3 domains and their targets.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ren, R -- Mayer, B J -- Cicchetti, P -- Baltimore, D -- CA 08875/CA/NCI NIH HHS/ -- CA 09673/CA/NCI NIH HHS/ -- CA 51462/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1993 Feb 19;259(5098):1157-61.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Rockefeller University, New York, NY 10021.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8438166" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Binding Sites ; Cytoskeletal Proteins/genetics/*metabolism ; DNA/genetics/metabolism ; Genes, abl ; Glutathione Transferase/genetics/metabolism ; Kinetics ; Mice ; Molecular Sequence Data ; *Proline ; Proto-Oncogene Proteins c-abl/genetics/*metabolism ; Rats ; Receptors, Muscarinic/metabolism ; Recombinant Fusion Proteins/metabolism ; Sequence Homology, Amino Acid ; Signal Transduction
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    NF-kappa B controls expression of inhibitor I kappa B alpha: evidence for an inducible autoregulatory pathway (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-03-26
    Description: The eukaryotic transcription factor nuclear factor-kappa B (NF-kappa B) participates in many parts of the genetic program mediating T lymphocyte activation and growth. Nuclear expression of NF-kappa B occurs after its induced dissociation from its cytoplasmic inhibitor I kappa B alpha. Phorbol ester and tumor necrosis factor-alpha induction of nuclear NF-kappa B is associated with both the degradation of performed I kappa B alpha and the activation of I kappa B alpha gene expression. Transfection studies indicate that the I kappa B alpha gene is specifically induced by the 65-kilodalton transactivating subunit of NF-kappa B. Association of the newly synthesized I kappa B alpha with p65 restores intracellular inhibition of NF-kappa B DNA binding activity and prolongs the survival of this labile inhibitor. Together, these results show that NF-kappa B controls the expression of I kappa B alpha by means of an inducible autoregulatory pathway.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sun, S C -- Ganchi, P A -- Ballard, D W -- Greene, W C -- 5T32CA09111/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1993 Mar 26;259(5103):1912-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Gladstone Institute of Virology and Immunology, University of California, San Francisco.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8096091" target="_blank"〉PubMed〈/a〉
    Keywords: CD4-Positive T-Lymphocytes/metabolism ; Cell Line ; Cell Nucleus/metabolism ; Cycloheximide/pharmacology ; Cytoplasm/metabolism ; DNA/metabolism ; DNA-Binding Proteins/*genetics ; *Gene Expression Regulation ; Humans ; *I-kappa B Proteins ; Immunoblotting ; Kinetics ; Molecular Weight ; Mutagenesis ; NF-kappa B/*antagonists & inhibitors/genetics/*physiology ; RNA, Messenger/biosynthesis ; Tetradecanoylphorbol Acetate/pharmacology ; Trans-Activators/pharmacology ; Transfection ; Tumor Necrosis Factor-alpha/pharmacology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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    The effect of posttranslational modifications on the interaction of Ras2 with adenylyl cyclase (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-01-29
    Description: Ras proteins undergo a series of posttranslational modifications that are critical for their cellular function. These modifications are necessary to anchor Ras proteins to the membrane. Yeast Ras2 proteins were purified with various degrees of modification and examined for their ability to activate their effector, adenylyl cyclase. The farnesylated intermediate form of Ras2 had more than 100 times higher affinity for adenylyl cyclase than for the unprocessed form. The subsequent palmitoylation reaction had little effect. In contrast, palmitoylation was required for efficient membrane localization of the Ras2 protein. These results indicate the importance of farnesylation in the interaction of Ras2 with its effector.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kuroda, Y -- Suzuki, N -- Kataoka, T -- New York, N.Y. -- Science. 1993 Jan 29;259(5095):683-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology, Kobe University School of Medicine, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8430318" target="_blank"〉PubMed〈/a〉
    Keywords: Adenylyl Cyclases/genetics/isolation & purification/*metabolism ; Amino Acid Sequence ; Animals ; Base Sequence ; Cell Line ; Cell Membrane/enzymology ; Electrophoresis, Polyacrylamide Gel ; Enzyme Activation ; Fungal Proteins/genetics/isolation & purification/*metabolism ; GTP-Binding Proteins/genetics/*metabolism ; Genes, Fungal ; Guanosine 5'-O-(3-Thiotriphosphate)/metabolism ; Insects ; Kinetics ; Molecular Sequence Data ; Molecular Weight ; Oligodeoxyribonucleotides ; Palmitic Acid ; Palmitic Acids/metabolism ; Protein Binding ; *Protein Processing, Post-Translational ; Recombinant Fusion Proteins/isolation & purification/metabolism ; Saccharomyces cerevisiae/genetics/*metabolism ; *Saccharomyces cerevisiae Proteins ; Transfection ; *ras Proteins
    Print ISSN: 0036-8075
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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    Inhibition of neural crest cell attachment by integrin antisense oligonucleotides (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-01-29
    Description: Neural crest cell interactions with extracellular matrix molecules were analyzed with the use of antisense oligonucleotides to block synthesis of integrin subunits. When added to the culture medium of quail neural crest cells, selected antisense phosphorothiol oligonucleotides reduced the amounts of cell surface alpha 1 or beta 1 integrin subunits by up to 95 percent and inhibited neural crest cell attachment to laminin or fibronectin substrata. Differential effects on specific alpha integrins were noted after treatment with alpha-specific oligonucleotides. Cells recovered the ability to bind to substrata 8 to 16 hours after treatment with inhibitory oligonucleotides. The operation of at least three distinct alpha integrin subunits is indicated by substratum-selective inhibition of cell attachment.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lallier, T -- Bronner-Fraser, M -- 15527/PHS HHS/ -- New York, N.Y. -- Science. 1993 Jan 29;259(5095):692-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Developmental Biology Center, University of California, Irvine 92717.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8430321" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Base Sequence ; Cell Adhesion/*drug effects ; Chickens ; Dose-Response Relationship, Drug ; Humans ; Integrins/biosynthesis/*genetics/isolation & purification ; Kinetics ; Macromolecular Substances ; Molecular Sequence Data ; Neural Crest/cytology/drug effects/*physiology ; Oligonucleotides, Antisense/*pharmacology ; Rats ; Structure-Activity Relationship
    Print ISSN: 0036-8075
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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    Detection of transient protein folding populations by mass spectrometry (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-11-05
    Description: Hydrogen-deuterium exchange measurements are becoming increasingly important in studies of the dynamics of protein molecules and, particularly, of their folding behavior. Electrospray ionization mass spectrometry (ESI-MS) has been used to obtain the distribution of masses within a population of protein molecules that had undergone hydrogen exchange in solution. This information is complementary to that from nuclear magnetic resonance spectroscopy (NMR) experiments, which measure the average occupancy of individual sites over the distribution of protein molecules. In experiments with hen lysozyme, a combination of ESI-MS and NMR was used to distinguish between alternative mechanisms of hydrogen exchange, providing insight into the nature and populations of transient folding intermediates. These results have helped to detail the pathways available to a protein during refolding.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Miranker, A -- Robinson, C V -- Radford, S E -- Aplin, R T -- Dobson, C M -- New York, N.Y. -- Science. 1993 Nov 5;262(5135):896-900.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Oxford Centre for Molecular Sciences, Oxford University, United Kingdom.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8235611" target="_blank"〉PubMed〈/a〉
    Keywords: Hydrogen/chemistry ; Hydrogen-Ion Concentration ; Kinetics ; Magnetic Resonance Spectroscopy ; Mass Spectrometry ; Models, Chemical ; Muramidase/*chemistry ; *Protein Folding ; Temperature
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    Tyrosine phosphorylation of actin in Dictyostelium associated with cell-shape changes (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-01-08
    Description: When Dictyostelium cells that have initiated their developmental program upon starvation are returned to growth medium, there is a rapid and transient de novo tyrosine phosphorylation of a 43-kilodalton protein. This protein was found to be actin. Most of the phosphorylation occurred in a single, minor acidic isoform of actin. Developing cells that had been returned to growth medium lost their pseudopod extensions, became round, and had reduced adhesion to the substratum. These effects occurred with kinetics that matched the increase in tyrosine phosphorylation of actin. In mutant cell lines in which the gene for the phosphotyrosine phosphatase PTP1 had been disrupted, tyrosine phosphorylation of actin was rapid and more prolonged. These cells responded with proportionally accelerated kinetics of cell rounding. Cell lines overexpressing PTP1 had diminished amplitude and duration of actin tyrosine phosphorylation and exhibited diminished cell-shape change and an accelerated return to the extended cell-shape morphology seen in starved cells.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Howard, P K -- Sefton, B M -- Firtel, R A -- New York, N.Y. -- Science. 1993 Jan 8;259(5092):241-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, University of California, San Diego, La Jolla 92093.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7678470" target="_blank"〉PubMed〈/a〉
    Keywords: Actins/*metabolism ; Animals ; Cell Adhesion ; Cell Membrane/metabolism ; Dictyostelium/*cytology/growth & development/*metabolism ; Immunoblotting ; Immunosorbent Techniques ; Kinetics ; Phosphotyrosine ; Tyrosine/*analogs & derivatives/metabolism
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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    Controlling chemical reactivity with antibodies (1993)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1993-04-16
    Description: The remarkable specificity of an antibody molecule has been used to accomplish highly selective functional group transformations not attainable by current chemical methods. An antibody raised against an amine-oxide hapten catalyzes the reduction of a diketone to a hydroxyketone with greater than 75:1 regioselectivity for one of two nearly equivalent ketone moieties. The antibody-catalyzed reaction is highly stereoselective, affording the hydroxyketone in high enantiomeric excess. Similarly, the reduction of ketones containing branched and aryl substituents, including the highly symmetrical 1-nitrophenyl-3-phenyl-2-propanone, was enantioselective. The simple strategy presented herein may find general applicability to the regio- and stereoselective reduction of a broad range of compounds.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hsieh, L C -- Yonkovich, S -- Kochersperger, L -- Schultz, P G -- New York, N.Y. -- Science. 1993 Apr 16;260(5106):337-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of California, Berkeley 94720.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/10049109" target="_blank"〉PubMed〈/a〉
    Keywords: Antibodies, Catalytic/*chemistry ; Antibodies, Monoclonal/chemistry ; Haptens ; Ketones/*chemistry ; Kinetics ; Oxidation-Reduction ; Propiophenones/chemistry ; Stereoisomerism
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    Electronic Resource
    Electronic Resource
    A temperature-jump device for time-resolved cryo-transmission electron microscopy (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 20 (1992), S. 95-101 
    Details
    ISSN: 1059-910X
    Keywords: Phosphatidylcholine ; Docosane ; Kinetics ; Phase transitions ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We describe a temperature-jump device that permits time-resolved studies of thin cryo-transmission electron microscopy specimens. The specimen is rapidly heated to induce a change in microstructure just prior to cryo-fixation. The apparatus consists of a xenon arc lamp equipped with a shutter controlled by timing circuitry, used in conjunction with an environmental specimen preparation chamber. The specimen is heated by exposure to focused light from the lamp, and then plunged into cryogen. Using a thermocouple constructed from an electron microscope grid, we show that temperature jumps of 30-60 K are achieved with exposure times of 150-450 milliseconds. Micrographs of dimyristoyl phosphatidylcholine (DMPC) vesicles and n-docosane films, subjected to these exposures, shew that the specimens are still at least 20-30 K above their initial temperature when they contact the cryogen. This method could be applied to a variety of biological and chemical systems which undergo structural changes activated by a rise in temperature.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070200110
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    Electronic Resource
    Electronic Resource
    Ester von (Hydroxymethyl)diorganylsilanen: Synthese und thermisch induzierte Umlagerung (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 591-605 
    Details
    ISSN: 0009-2940
    Keywords: (Hydroxymethyl)diorganylsilanes, esters of ; Rearrangement, thermally induced ; Kinetics ; DSC ; Calculations, ab initio ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Esters of (Hydroxymethyl)diorganylsilanes: Synthesis and Thermally Induced RearrangementTwenty silanes of the type R1R2Si(H)CH2OR3 (A) were synthesized [R1, R2 = Me, Ph, 1-naphthyl, PhCH2,Me3SiCH2; OR3 = OC(O)Me, OC(O)Ph, OC(O)CF3, OS(O)2CF3, OP(O)Ph2, OC(O)Cl] and studied for their thermal behaviour. The silanes A undergo a thermally induced rearrangement to give the corresponding silanes R1R2Si(OR3)Me (B). For compounds with OR3 = OC(O)Cl, an additional decarboxylation takes place to yield the chlorosilanes R1R2Si(Cl)Me. Except for the derivatives with OR3 = OC(O)Cl, the energetic (reaction enthalpy) and kinetic data (reaction order, frequency factor, enthalpy and entropy of activation) of these reactions were studied by means of differential scanning calorimetry (DSC). In addition, the kinetics of all reactions were investigated by 1H-NMR spectroscopy. The transition state of the rearrangement was investigated by an ab initio study based on the model compound H3SiCH2OC(O)H [→ MeH2SiOC(O)H]. The theoretical data and the experimentally obtained energetic and kinetic data are discussed in terms of mechanistic aspects of the rearrangement reaction A → B.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250310
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    Electronic Resource
    Electronic Resource
    trans-1-(Dimethylamino)-1,3-butadiene - Concerted and Stepwise (4 + 2) Cycloadditions (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 1647-1656 
    Details
    ISSN: 0009-2940
    Keywords: Cycloadditions ; Diels-Alder reactions ; Kinetics ; Zwitterionic intermediates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: trans-1-(Dimethylamino)-1,3-butadiene is allowed to react with methyl acrylate, acrylonitrile, maleo- and fumaronitrile, dimethyl maleate and fumarate, as well as with dimethyl dicyanomaleate and dicyanofumarate. In all cases except the two last ones where only a single isomer is obtained mixtures (endo/exo) of cycloadducts are formed. Structures are determined by a combination of one- and two-dimensional NMR spectroscopy. The E/Z isomeric maleo- and fumaronitrile add stereospecifically to the diene. Cycloaddition of dimethyl maleate and fumarate leads to the same mixture of isomers in almost the same ratio. The reaction of dimethyl dicyanomaleate and dimethyl dicyanofumarate yields a cycloadduct which seems to be the thermodynamically most stable one. The results are interpreted in such a manner that a concerted cycloaddition takes place with maleo- and fumaronitrile, while stepwise reactions, presumably proceeding via zwitterions, are observed with dimethyl maleate, fumarate, the strongly electrophilic dimethyl dicyanomaleate and dicyanofumarate. With increasing capability of the dienophile to stabilize a negative charge the mechanism changes from a concerted to a stepwise reaction.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250721
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    Diverse migratory pathways in the developing cerebral cortex (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-10-09
    Description: During early development of the mammalian cerebral cortex, young neurons migrate outward from the site of their final mitosis in the ventricular zone into the cortical plate, where they form the adult cortex. Time-lapse confocal microscopy was used to observe directly the dynamic behaviors of migrating cells in living slices of developing cortex. The majority of cells migrated along a radial pathway, consistent with the view that cortical neurons migrate along radial glial fibers. A fraction of cells, however, turned within the intermediate zone and migrated orthogonal to the radial fibers. This orthogonal migration may contribute to the tangential dispersion of clonally related cortical neurons.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉O'Rourke, N A -- Dailey, M E -- Smith, S J -- McConnell, S K -- EY06314/EY/NEI NIH HHS/ -- NS09027/NS/NINDS NIH HHS/ -- NS28587/NS/NINDS NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1992 Oct 9;258(5080):299-302.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Sciences, Stanford University, CA 94305.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1411527" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antibodies, Monoclonal ; Carbocyanines ; Cell Movement ; Cerebral Cortex/cytology/*growth & development ; Culture Techniques ; Ferrets ; Fluorescent Dyes ; Immunohistochemistry ; Kinetics ; Lasers ; Microscopy ; Neurons/*physiology ; Vimentin/immunology
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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    Cooperativity induced by a single mutation at the subunit interface of a dimeric enzyme: glutathione reductase (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-11-13
    Description: When glycine418 of Escherichia coli glutathione reductase, which is in a closely packed region of the dimer interface, is replaced with a bulky tryptophan residue, the enzyme becomes highly cooperative (Hill coefficient 1.76) for glutathione binding. The cooperativity is lost when the mutant subunit is hybridized with a wild-type subunit to create a heterodimer. The mutation appears to disrupt atomic packing at the dimer interface, which induces a change of kinetic mechanism. A single mutation in a region of the protein remote from the active site can thus act as a molecular switch to confer cooperativity on an enzyme.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Scrutton, N S -- Deonarain, M P -- Berry, A -- Perham, R N -- New York, N.Y. -- Science. 1992 Nov 13;258(5085):1140-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of Cambridge, United Kingdom.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1439821" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Binding Sites ; Escherichia coli/*enzymology/genetics ; Genes, Bacterial ; Glutathione/metabolism ; Glutathione Reductase/*chemistry/genetics/metabolism ; Glycine/chemistry ; Kinetics ; Macromolecular Substances ; Models, Molecular ; Molecular Sequence Data ; Molecular Structure ; *Mutagenesis, Site-Directed ; NADP/metabolism ; Plasmids ; Protein Multimerization ; Tryptophan/chemistry
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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    Diacylglycerol-stimulated formation of actin nucleation sites at plasma membranes (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-04-10
    Description: Diacylglycerols, which are generated during phospholipase-catalyzed hydrolysis of phospholipids, stimulated actin polymerization in the presence of highly purified plasma membranes from the cellular slime mold Dictyostelium discoideum. The increased rate of actin polymerization apparently resulted from de novo formation of actin nucleation sites rather than uncapping of existing filament ends, because the membranes lacked detectable endogenous actin. The increased actin nucleation was mediated by a peripheral membrane component other than protein kinase C, the classical target of diacylglycerol action. These results indicate that diacylglycerols increase actin nucleation at plasma membranes and suggest a mechanism whereby signal transduction pathways may control cytoskeletal assembly.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shariff, A -- Luna, E J -- GM-33048/GM/NIGMS NIH HHS/ -- R01 GM033048/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1992 Apr 10;256(5054):245-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cell Biology Group, Worcester Foundation for Experimental Biology, Shresbury, MA 01545.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1373523" target="_blank"〉PubMed〈/a〉
    Keywords: Actins/*metabolism ; Alkaloids/pharmacology ; Animals ; Calcium/pharmacology ; Cell Membrane/drug effects/*metabolism ; Dictyostelium/*metabolism ; Diglycerides/*pharmacology ; Kinetics ; Macromolecular Substances ; *Naphthalenes ; Polycyclic Compounds/pharmacology ; Protein Kinase C/antagonists & inhibitors ; Staurosporine ; Tetradecanoylphorbol Acetate/pharmacology ; Time Factors
    Print ISSN: 0036-8075
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    DNA hydrolyzing autoantibodies (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-05-01
    Description: A DNA-nicking activity was detected in the sera of patients with various autoimmune pathologies and was shown to be a property of autoantibodies. The DNA hydrolyzing activity, which was purified by affinity and high-performance liquid chromatography, corresponded in size to immunoglobulin M (IgM) and IgG and had a positive response to antibodies to human IgG. The DNA hydrolyzing autoantibodies were stable to acid shock and yielded a DNA degradation pattern that was different from that of deoxyribonuclease (DNase) I and blood DNase.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shuster, A M -- Gololobov, G V -- Kvashuk, O A -- Bogomolova, A E -- Smirnov, I V -- Gabibov, A G -- New York, N.Y. -- Science. 1992 May 1;256(5057):665-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉V.A. Engelhardt Institute of Molecular Biology, Academy of Sciences of Russia, Moscow.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1585181" target="_blank"〉PubMed〈/a〉
    Keywords: Acetates/pharmacology ; Acetic Acid ; Autoantibodies/isolation & purification/*metabolism ; Autoimmune Diseases/*metabolism ; Chromatography, High Pressure Liquid ; DNA/*metabolism ; DNA Polymerase I/metabolism ; Deoxyribonuclease I/metabolism ; Electrophoresis, Agar Gel ; Humans ; Immunoglobulin G/isolation & purification/metabolism ; Immunoglobulin M/isolation & purification/metabolism ; Kinetics ; Lupus Erythematosus, Systemic/immunology ; Plasmids
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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    Cloning and expression in yeast of a plant potassium ion transport system (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-05-01
    Description: A membrane polypeptide involved in K+ transport in a higher plant was cloned by complementation of a yeast mutant defective in K+ uptake with a complementary DNA library from Arabidopsis thaliana. A 2.65-kilobase complementary DNA conferred ability to grow on media with K+ concentration in the micromolar range and to absorb K+ (or 86Rb+) at rates similar to those in wild-type yeast. The predicted amino acid sequence (838 amino acids) has three domains: a channel-forming region homologous to animal K+ channels, a cyclic nucleotide-binding site, and an ankyrin-like region.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sentenac, H -- Bonneaud, N -- Minet, M -- Lacroute, F -- Salmon, J M -- Gaymard, F -- Grignon, C -- New York, N.Y. -- Science. 1992 May 1;256(5057):663-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Biochimie et Physiologie Vegetales, ENSA-M/INRA/CNRS URA 573, Montpellier, France.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1585180" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; *Arabidopsis Proteins ; Biological Transport ; Blotting, Southern ; Carrier Proteins/chemistry/genetics ; *Cloning, Molecular ; DNA/genetics ; Deoxyribonuclease EcoRI ; Gene Expression ; Kinetics ; Molecular Sequence Data ; Plant Proteins/chemistry/*genetics ; Plants/*genetics ; Potassium/*metabolism ; Potassium Channels/chemistry/*genetics ; Saccharomyces cerevisiae/*genetics ; Sequence Homology, Nucleic Acid
    Print ISSN: 0036-8075
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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    Pseudo--half-knot formation with RNA (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-08-14
    Description: A pseudo--half-knot can be formed by binding an oligonucleotide asymmetrically to an RNA hairpin loop. This binding motif was used to target the human immunodeficiency virus TAR element, an important viral RNA structure that is the receptor for Tat, the major viral transactivator protein. Oligonucleotides complementary to different halves of the TAR structure bound with greater affinity than molecules designed to bind symmetrically around the hairpin. The pseudo--half-knot--forming oligonucleotides altered the TAR structure so that specific recognition and binding of a Tat-derived peptide was disrupted. This general binding motif may be used to disrupt the structure of regulatory RNA hairpins.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ecker, D J -- Vickers, T A -- Bruice, T W -- Freier, S M -- Jenison, R D -- Manoharan, M -- Zounes, M -- New York, N.Y. -- Science. 1992 Aug 14;257(5072):958-61.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉ISIS Pharmaceuticals, Carlsbad, CA 92008.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1502560" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Binding Sites ; DNA, Viral/metabolism ; Gene Products, tat/metabolism ; HIV/*genetics ; Kinetics ; Molecular Sequence Data ; *Nucleic Acid Conformation ; Oligoribonucleotides/*chemistry ; RNA, Viral/*chemistry/genetics/metabolism ; tat Gene Products, Human Immunodeficiency Virus
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  • 82
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    G protein activation of a hormone-stimulated phosphatase in human tumor cells (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-05-22
    Description: The growth-inhibiting peptide hormone somatostatin stimulates phosphotyrosine phosphatase activity in the human pancreatic cell line MIA PaCa-2. This hormonal activation was mediated by a pertussis toxin-sensitive guanosine 5'-triphosphate-binding protein (G protein) in the membranes of these cells. Activation of this G protein by somatostatin stimulated the dephosphorylation of exogenous epidermal growth factor receptor prepared from A-431 cells in vitro. This pathway may mediate the antineoplastic action of somatostatin in these cells and in human tumors and could represent a general mechanism of G protein coupling that is utilized by normal cells in the hormonal control of cell growth.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pan, M G -- Florio, T -- Stork, P J -- New York, N.Y. -- Science. 1992 May 22;256(5060):1215-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Vollum Institute for Advanced Biomedical Research, Oregon Health Sciences University, Portland 97201.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1350382" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphate/metabolism ; Carcinoma, Squamous Cell ; Cell Line ; Cell Membrane/metabolism ; Dose-Response Relationship, Drug ; Enzyme Activation ; GTP-Binding Proteins/*metabolism ; Guanosine 5'-O-(3-Thiotriphosphate)/pharmacology ; Guanosine Diphosphate/analogs & derivatives/pharmacology ; Humans ; Kinetics ; Pancreatic Neoplasms ; Peptides/metabolism ; Pertussis Toxin ; Phosphorylation ; Protein Kinases/metabolism ; Protein Tyrosine Phosphatases/*metabolism ; Receptor, Epidermal Growth Factor/metabolism ; Somatostatin/*pharmacology ; Thionucleotides/pharmacology ; Virulence Factors, Bordetella/pharmacology
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  • 83
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    Dimerization of a specific DNA-binding protein on the DNA (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-01-10
    Description: Many specific DNA-binding proteins bind to sites with dyad symmetry, and the bound form of the protein is a dimer. For some proteins, dimers form in solution and bind to DNA. LexA repressor of Escherichia coli has been used to test an alternative binding model in which two monomers bind sequentially. This model predicts that a repressor monomer should bind with high specificity to an isolated operator half-site. Monomer binding to a half-site was observed. A second monomer bound to an intact operator far more tightly than the first monomer; this cooperativity arose from protein-protein contacts.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kim, B -- Little, J W -- GM24178/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1992 Jan 10;255(5041):203-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of Arizona, Tucson 85721.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1553548" target="_blank"〉PubMed〈/a〉
    Keywords: Bacterial Proteins/*metabolism ; Base Sequence ; Binding Sites ; DNA, Bacterial/*metabolism ; DNA-Binding Proteins/*metabolism ; Deoxyribonucleases ; Escherichia coli/*metabolism ; Kinetics ; Macromolecular Substances ; Models, Structural ; Molecular Sequence Data ; Oligodeoxyribonucleotides/metabolism ; Operon ; Rec A Recombinases/genetics ; Repressor Proteins/metabolism ; *Serine Endopeptidases
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  • 84
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    Converting trypsin to chymotrypsin: the role of surface loops (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-03-06
    Description: Trypsin (Tr) and chymotrypsin (Ch) have similar tertiary structures, yet Tr cleaves peptides at arginine and lysine residues and Ch prefers large hydrophobic residues. Although replacement of the S1 binding site of Tr with the analogous residues of Ch is sufficient to transfer Ch specificity for ester hydrolysis, specificity for amide hydrolysis is not transferred. Trypsin is converted to a Ch-like protease when the binding pocket alterations are further modified by exchange of the Ch surface loops 185 through 188 and 221 through 225 for the analogous Tr loops. These loops are not structural components of either the S1 binding site or the extended substrate binding sites. This mutant enzyme is equivalent to Ch in its catalytic rate, but its substrate binding is impaired. Like Ch, this mutant utilizes extended substrate binding to accelerate catalysis, and substrate discrimination occurs during the acylation step rather than in substrate binding.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hedstrom, L -- Szilagyi, L -- Rutter, W J -- DK21344/DK/NIDDK NIH HHS/ -- New York, N.Y. -- Science. 1992 Mar 6;255(5049):1249-53.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Hormone Research Institute, University of California, San Francisco 94143-0534.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1546324" target="_blank"〉PubMed〈/a〉
    Keywords: Acylation ; Amino Acid Sequence ; Base Sequence ; Binding Sites ; Chymotrypsin/*chemistry/metabolism ; Hydrolysis ; Kinetics ; Models, Molecular ; Molecular Sequence Data ; Molecular Structure ; Mutagenesis, Site-Directed ; Protein Conformation ; Substrate Specificity ; Trypsin/*chemistry/genetics/metabolism
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  • 85
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    Removal of nonhomologous DNA ends in double-strand break recombination: the role of the yeast ultraviolet repair gene RAD1 (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-10-16
    Description: Double-strand breaks (DSBs) in Saccharomyces cerevisiae can be repaired by gene conversions or by deletions resulting from single-strand annealing between direct repeats of homologous sequences. Although rad1 mutants are resistant to x-rays and can complete DSB-mediated mating-type switching, they could not complete recombination when the ends of the break contained approximately 60 base pairs of nonhomology. Recombination was restored when the ends of the break were made homologous to donor sequences. Additionally, the absence of RAD1 led to the frequent appearance of a previously unobserved type of recombination product. These data suggest RAD1 is required to remove nonhomologous DNA from the 3' ends of recombining DNA, a process analogous to the excision of photodimers during repair of ultraviolet-damaged DNA.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fishman-Lobell, J -- Haber, J E -- GM01722/GM/NIGMS NIH HHS/ -- GM20056/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1992 Oct 16;258(5081):480-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02254.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1411547" target="_blank"〉PubMed〈/a〉
    Keywords: *DNA Repair ; DNA, Fungal/genetics ; Deoxyribonucleases, Type II Site-Specific/*metabolism ; Gene Conversion ; Kinetics ; *Recombination, Genetic ; Saccharomyces cerevisiae/*genetics ; Saccharomyces cerevisiae Proteins ; Sequence Deletion ; Ultraviolet Rays
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  • 86
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    Antibody-catalyzed rearrangement of the peptide bond (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-10-30
    Description: The generation of antibodies from a bifunctional cyclic phosphinate transition-state analog provided agents capable of efficiently catalyzing both steps of the overall conversion of a substrate containing an asparaginyl-glycyl sequence through a succinimide intermediate to the products aspartyl-glycyl and the rearranged isoaspartyl-glycyl sequence. This reaction provides a potential means in addition to amide cleavage for the deactivation of protein or peptide biological functions in vivo.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gibbs, R A -- Taylor, S -- Benkovic, S J -- New York, N.Y. -- Science. 1992 Oct 30;258(5083):803-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Pennsylvania State University, University Park 16802.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1439788" target="_blank"〉PubMed〈/a〉
    Keywords: Antibodies, Catalytic/*metabolism ; Asparagine/metabolism ; Aspartic Acid/metabolism ; Chromatography, High Pressure Liquid ; Dipeptides/metabolism ; Glycine/metabolism ; Hydrogen-Ion Concentration ; Kinetics ; Peptides/chemistry/*metabolism ; Stereoisomerism ; Succinimides/metabolism
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  • 87
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    Tertiary structure around the guanosine-binding site of the Tetrahymena ribozyme (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-04-24
    Description: A cleavage reagent directed to the active site of the Tetrahymena catalytic RNA was synthesized by derivatization of the guanosine substrate with a metal chelator. When complexed with iron(II), this reagent cleaved the RNA in five regions. Cleavage at adenosine 207, which is far from the guanosine-binding site in the primary and secondary structure, provides a constraint for the higher order folding of the RNA. This cleavage site constitutes physical evidence for a key feature of the Michel-Westhof model. Targeting a reactive entity to a specific site should be generally useful for determining proximity within folded RNA molecules or ribonucleoprotein complexes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wang, J F -- Cech, T R -- New York, N.Y. -- Science. 1992 Apr 24;256(5056):526-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Colorado, Boulder 80309-0215.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1315076" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Base Sequence ; Binding Sites ; Edetic Acid/metabolism ; Free Radicals ; Guanosine/*metabolism ; Guanosine Monophosphate/metabolism ; Iron/metabolism ; Iron Chelating Agents/metabolism ; Kinetics ; Models, Molecular ; Molecular Sequence Data ; Molecular Structure ; Nucleic Acid Conformation ; Pentetic Acid/metabolism ; RNA, Catalytic/*chemistry/metabolism ; Tetrahymena/*chemistry
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  • 88
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    Calcium-dependent transmitter secretion reconstituted in Xenopus oocytes: requirement for synaptophysin (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-07-31
    Description: Calcium-dependent glutamate secretion was reconstituted in Xenopus oocytes by injecting the oocyte with total rat cerebellar messenger RNA (mRNA). Co-injection of total mRNA with antisense oligonucleotides to synaptophysin message decreased the expression of synaptophysin in the oocyte and reduced the calcium-dependent secretion. A similar effect on secretion was observed for oocytes injected with total mRNA together with an antibody to rat synaptophysin. These results indicate that synaptophysin is necessary for transmitter secretion and that the oocyte expression system may be useful for dissecting the molecular events associated with the secretory process.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Alder, J -- Lu, B -- Valtorta, F -- Greengard, P -- Poo, M M -- MH 39327/MH/NIMH NIH HHS/ -- NS 22764/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1992 Jul 31;257(5070):657-61.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Sciences, Columbia University, New York, NY 10027.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1353905" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Base Sequence ; Blotting, Western ; Calcimycin/pharmacology ; Calcium/*pharmacology ; Cerebellum/chemistry ; Fluorescent Antibody Technique ; Gene Expression ; Glutamates/*secretion ; Glutamic Acid ; Kinetics ; Liver/chemistry ; Microscopy, Immunoelectron ; Molecular Sequence Data ; Oligonucleotides, Antisense/pharmacology ; Oocytes/*physiology ; RNA, Messenger/genetics ; Rats ; Synaptophysin/genetics/*physiology ; Transfection ; Xenopus
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  • 89
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    Regulation of dynein-driven microtubule sliding by the radial spokes in flagella (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-09-11
    Description: The regulation of microtubule sliding in flagellar axonemes was studied with the use of Chlamydomonas mutants and in vitro assays. Microtubule sliding velocities were diminished in axonemes from mutant cells missing radial spoke structures but could be restored upon reconstitution with dynein from axonemes with wild-type radial spokes. These experiments demonstrate that the radial spokes activate dynein's microtubule sliding activity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Smith, E F -- Sale, W S -- GM 08367/GM/NIGMS NIH HHS/ -- HD 20497/HD/NICHD NIH HHS/ -- New York, N.Y. -- Science. 1992 Sep 11;257(5076):1557-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Anatomy and Cell Biology, Emory University School of Medicine, Atlanta, GA 30322.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1387971" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Movement ; Chlamydomonas/genetics/*physiology/ultrastructure ; Dyneins/genetics/*metabolism ; Flagella/*physiology/ultrastructure ; Kinetics ; Microscopy, Electron ; Microtubules/*physiology/ultrastructure
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  • 90
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    Participation of non-zinc finger residues in DNA binding by two nuclear orphan receptors (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-04-03
    Description: Steroid-thyroid hormone receptors typically bind as dimers to DNA sequences that contain repeated elements termed half-sites. NGFI-B, an early response protein and orphan member of this receptor superfamily, binds to a DNA sequence that contains only one half-site (5'-AAAGGTCA-3'). A domain separate from the NGFI-B zinc fingers, termed the A box, was identified and is required for recognition of the two adenine-thymidine (A-T) base pairs at the 5' end of the NGFI-B DNA binding element. In addition, a domain downstream of the zinc fingers of the orphan receptor H-2 region II binding protein, termed the T box, determined binding to tandem repeats of the estrogen receptor half-site (5'-AGGTCA-3').〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wilson, T E -- Paulsen, R E -- Padgett, K A -- Milbrandt, J -- NS01018/NS/NINDS NIH HHS/ -- P01 CA49712/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1992 Apr 3;256(5053):107-10.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pathology, Washington University School of Medicine, St. Louis, MO 63110.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1314418" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Base Sequence ; Binding Sites ; CHO Cells ; Cell Nucleus/*physiology ; Cricetinae ; DNA/*metabolism ; DNA-Binding Proteins/genetics/*metabolism ; Kinetics ; Mice ; Molecular Sequence Data ; Nuclear Receptor Subfamily 4, Group A, Member 1 ; Oligodeoxyribonucleotides/metabolism ; Polymerase Chain Reaction ; Receptors, Cell Surface/*metabolism ; Receptors, Cytoplasmic and Nuclear ; Receptors, Steroid ; Recombinant Fusion Proteins/metabolism ; Sequence Homology, Nucleic Acid ; Substrate Specificity ; Transcription Factors/genetics/*metabolism ; Transfection ; Zinc Fingers/genetics
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  • 91
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    Mechanism of DNA strand transfer reactions catalyzed by HIV-1 reverse transcriptase (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-11-13
    Description: Two DNA strand transfer reactions occur during retroviral reverse transcription. The mechanism of the first, minus strand strong-stop DNA, transfer has been studied in vitro with human immunodeficiency virus 1 reverse transcriptase (HIV-1 RT) and a model template-primer system derived from the HIV-1 genome. The results reveal that HIV-1 RT alone can catalyze DNA strand transfer reactions. Two kinetically distinct ribonuclease (RNase) H activities associated with HIV-1 RT are required for removal of RNA fragments annealed to the nascent DNA strand. Examination of the binding of DNA.RNA duplex and single-stranded RNA to HIV-1 RT during strand transfer supports a model where the enzyme accommodates both the acceptor RNA template and the nascent DNA strand before the transfer event is completed. The polymerase activity incorporated additional bases beyond the 5' end of the RNA template, resulting in a base misincorporation upon DNA strand transfer. Such a process occurring in vivo during retroviral homologous recombination could contribute to the hypermutability of the HIV-1 genome.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Peliska, J A -- Benkovic, S J -- AI08275/AI/NIAID NIH HHS/ -- GM13306/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1992 Nov 13;258(5085):1112-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Pennsylvania State University, University Park 16802.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1279806" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Catalysis ; DNA, Viral/biosynthesis/chemistry/*metabolism ; Deoxyribonucleotides ; HIV Reverse Transcriptase ; HIV-1/*enzymology/genetics ; Kinetics ; Molecular Sequence Data ; Mutation ; Nucleic Acid Hybridization ; RNA, Transfer/metabolism ; RNA, Viral/chemistry/metabolism ; RNA-Directed DNA Polymerase/genetics/*metabolism ; Ribonuclease H/metabolism ; Templates, Genetic
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  • 92
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    High-efficiency expression and solubilization of functional T cell antigen receptor heterodimers (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-05-29
    Description: The T cell receptor (TCR) zeta chain was attached to the TCR alpha and beta extracellular domains to induce efficient expression of alpha beta heterodimers that can recognize complexes of antigen with major histocompatibility complex (MHC) molecules. Chimeric constructs expressed in RBL-2H3 cells were efficiently transported to the cell surface uniquely as disulfide-linked heterodimers. Transfectants were activated by specific antigen-MHC complexes, which demonstrated that the expressed alpha beta was functional and that CD3 was not required for antigen-MHC binding. Constructs with thrombin cleavage sites were efficiently cleaved to soluble disulfide-linked heterodimers. Thus, attachment of TCR zeta domains and protease cleavage sites to TCR alpha and beta induces expression of demonstrably functional heterodimers that can be solubilized.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Engel, I -- Ottenhoff, T H -- Klausner, R D -- New York, N.Y. -- Science. 1992 May 29;256(5061):1318-21.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1598575" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Cell Line ; Cell Membrane/immunology ; Disulfides ; Flow Cytometry ; Histocompatibility Antigens/metabolism ; Kinetics ; Macromolecular Substances ; Molecular Sequence Data ; Oligodeoxyribonucleotides ; Polymerase Chain Reaction ; Receptors, Antigen, T-Cell/genetics/isolation & purification/*metabolism ; Solubility ; Transfection
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  • 93
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    A surface protease and the invasive character of plague (1992)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1992-11-06
    Description: A 9.5-kilobase plasmid of Yersinia pestis, the causative agent of plague, is required for high virulence when mice are inoculated with the bacterium by subcutaneous injection. Inactivation of the plasmid gene pla, which encodes a surface protease, increased the median lethal dose of the bacteria for mice by a millionfold. Moreover, cloned pla was sufficient to restore segregants lacking the entire pla-bearing plasmid to full virulence. Both pla+ strains injected subcutaneously and pla- mutants injected intravenously reached high titers in liver and spleen of infected mice, whereas pla- mutants injected subcutaneously failed to do so even though they establish a sustained local infection at the injection site. More inflammatory cells accumulated in lesions caused by the pla- mutants than in lesions produced by the pla+ parent. The Pla protease was shown to be a plasminogen activator with unusual kinetic properties. It can also cleave complement C3 at a specific site.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sodeinde, O A -- Subrahmanyam, Y V -- Stark, K -- Quan, T -- Bao, Y -- Goguen, J D -- AI22176/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 1992 Nov 6;258(5084):1004-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, Worcester 01655.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1439793" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; *Bacterial Proteins ; Colony Count, Microbial ; Escherichia coli/enzymology ; Fibrinolysin/chemistry/metabolism ; Injections, Intravenous ; Kinetics ; Liver/microbiology ; Mice ; Molecular Sequence Data ; Mutation ; Plague/microbiology ; Plasmids ; Plasminogen Activators/genetics/*physiology ; Recombinant Proteins/metabolism ; Spleen/microbiology ; Tissue Plasminogen Activator/metabolism ; Urokinase-Type Plasminogen Activator/metabolism ; Yersinia pestis/*enzymology/isolation & purification/*pathogenicity
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  • 94
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    Aminoacyl esterase activity of the Tetrahymena ribozyme (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-06-05
    Description: Several classes of ribozymes (catalytic RNA's) catalyze reactions at phosphorus centers, but apparently no reaction at a carbon center has been demonstrated. The active site of the Tetrahymena ribozyme was engineered to bind an oligonucleotide derived from the 3' end of N-formyl-methionyl-tRNA(fMet). This ribozyme catalyzes the hydrolysis of the aminoacyl ester bond to a modest extent, 5 to 15 times greater than the uncatalyzed rate. Catalysis involves binding of the oligonucleotide to the internal guide sequence of the ribozyme and requires Mg2+ and sequence elements of the catalytic core. The ability of RNA to catalyze reactions with aminoacyl esters expands the catalytic versatility of RNA and suggests that the first aminoacyl tRNA synthetase could have been an RNA molecule.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Piccirilli, J A -- McConnell, T S -- Zaug, A J -- Noller, H F -- Cech, T R -- New York, N.Y. -- Science. 1992 Jun 5;256(5062):1420-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Colorado, Boulder 80309.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1604316" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Base Sequence ; Binding Sites ; Carboxylic Ester Hydrolases/*metabolism ; Kinetics ; Models, Structural ; Molecular Sequence Data ; Nucleic Acid Conformation ; Oligoribonucleotides ; RNA, Catalytic/genetics/*metabolism ; RNA, Transfer, Amino Acyl/metabolism ; *RNA, Transfer, Met ; Substrate Specificity ; Tetrahymena/*enzymology
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 95
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    Cloning of a delta opioid receptor by functional expression (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-12-28
    Description: Opiate drugs have potent analgesic and addictive properties. These drugs interact with receptors that also mediate the response to endogenous opioid peptide ligands. However, the receptors for opioids have eluded definitive molecular characterization. By transient expression in COS cells and screening with an iodinated analog of the opioid peptide enkephalin, a complementary DNA clone encoding a functional delta opioid receptor has been identified. The sequence shows homology to G protein-coupled receptors, in particular the receptors for somatostatin, angiotensin, and interleukin-8.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Evans, C J -- Keith, D E Jr -- Morrison, H -- Magendzo, K -- Edwards, R H -- DA05010/DA/NIDA NIH HHS/ -- P50 DA005010/DA/NIDA NIH HHS/ -- New York, N.Y. -- Science. 1992 Dec 18;258(5090):1952-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Psychiatry, University of California, School of Medicine, Los Angeles 90024-1759.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1335167" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Binding, Competitive ; Blotting, Northern ; Blotting, Southern ; Cell Line ; Cyclic AMP/metabolism ; Diprenorphine/metabolism ; Enkephalin, D-Penicillamine (2,5)- ; Enkephalins/pharmacology ; Etorphine/pharmacology ; Gene Expression ; Humans ; Kinetics ; Models, Structural ; Molecular Sequence Data ; Naloxone/pharmacology ; Narcotics/pharmacology ; Protein Structure, Secondary ; Receptors, Opioid, delta/chemistry/*genetics/*metabolism ; Sequence Homology, Amino Acid ; Transfection ; Tumor Cells, Cultured
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 96
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    Cloning and characterization of inducible nitric oxide synthase from mouse macrophages (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-04-10
    Description: Nitric oxide (NO) conveys a variety of messages between cells, including signals for vasorelaxation, neurotransmission, and cytotoxicity. In some endothelial cells and neurons, a constitutive NO synthase is activated transiently by agonists that elevate intracellular calcium concentrations and promote the binding of calmodulin. In contrast, in macrophages, NO synthase activity appears slowly after exposure of the cells to cytokines and bacterial products, is sustained, and functions independently of calcium and calmodulin. A monospecific antibody was used to clone complementary DNA that encoded two isoforms of NO synthase from immunologically activated mouse macrophages. Liquid chromatography-mass spectrometry was used to confirm most of the amino acid sequence. Macrophage NO synthase differs extensively from cerebellar NO synthase. The macrophage enzyme is immunologically induced at the transcriptional level and closely resembles the enzyme in cytokine-treated tumor cells and inflammatory neutrophils.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Xie, Q W -- Cho, H J -- Calaycay, J -- Mumford, R A -- Swiderek, K M -- Lee, T D -- Ding, A -- Troso, T -- Nathan, C -- AI30165/AI/NIAID NIH HHS/ -- CA43610/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1992 Apr 10;256(5054):225-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Beatrice and Samuel A. Seaver Laboratory, Department of Medicine, Cornell University Medical College, New York, NY 10021.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1373522" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Oxidoreductases/biosynthesis/*genetics ; Amino Acid Sequence ; Animals ; Base Sequence ; Cell Line ; Cells, Cultured ; Cloning, Molecular ; Codon ; Enzyme Induction ; Interferon-gamma/pharmacology ; Isoenzymes/biosynthesis/*genetics ; Kinetics ; Lipopolysaccharides ; Macrophages/drug effects/*enzymology ; Mammary Neoplasms, Experimental ; Mice ; Molecular Sequence Data ; Molecular Weight ; Neutrophils/drug effects/enzymology ; Nitric Oxide Synthase ; Oligodeoxyribonucleotides ; Poly A/genetics ; RNA/genetics ; RNA, Messenger ; Rats ; Sequence Homology, Nucleic Acid ; Transcription, Genetic
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 97
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    Tyrosine phosphorylation of the vav proto-oncogene product in activated B cells (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-05-22
    Description: Activation of B lymphocytes by engagement of their immunoglobulin M antigen receptors results in phosphorylation of a number of proteins on tyrosine residues. One such protein is p95vav, the product of the vav proto-oncogene. Tyrosine phosphorylation of p95vav occurred within seconds of immunoglobulin M cross-linking and was independent of other events induced during stimulation of B cells, such as protein kinase C activation, guanosine triphosphate-binding protein signaling, and calcium mobilization. Moreover, engagement of antigen receptors induced the rapid (approximately 5 seconds) and transient (approximately 60 seconds) association of p95vav with a 70-kilodalton tyrosine-phosphorylated protein, Vap-1, an interaction mediated by the Src homology 2 domain of p95vav. These results suggest that the vav proto-oncogene participates in the signaling processes that mediate the antigen-induced activation of B lymphocytes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bustelo, X R -- Barbacid, M -- New York, N.Y. -- Science. 1992 May 22;256(5060):1196-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, NJ 08543-4000.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1375396" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acids/analysis ; Animals ; B-Lymphocytes/immunology/*physiology ; *Cell Cycle Proteins ; Cell Line ; Kinetics ; *Lymphocyte Activation ; Mice ; Phosphorylation ; Phosphotyrosine ; Polymerase Chain Reaction ; Protein-Tyrosine Kinases/*metabolism ; Proto-Oncogene Proteins/genetics/*metabolism ; Proto-Oncogene Proteins c-vav ; *Proto-Oncogenes ; Tyrosine/analogs & derivatives/analysis
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 98
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    Lithium-sensitive production of inositol phosphates during amphibian embryonic mesoderm induction (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-04-10
    Description: Mesoderm induction and body axis determination in frog (Xenopus) embryos are thought to involve growth factor-mediated cell-cell signaling, but the signal transduction pathways are unknown. Li+, which inhibits the polyphosphoinositide (PI) cycle signal transduction pathway in many cells, also disrupts axis determination and mesoderm induction. Amounts of the PI cycle-derived second messenger, inositol 1,4,5-trisphosphate, increased during mesoderm induction in normal embryos; addition of Li+ inhibited the embryonic inositol monophosphatase and reversed this increase. Embryonic PI cycle activity thus shows characteristics that indicate it may function in mesoderm induction and axis determination.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Maslanski, J A -- Leshko, L -- Busa, W B -- HD22879/HD/NICHD NIH HHS/ -- HD27546/HD/NICHD NIH HHS/ -- New York, N.Y. -- Science. 1992 Apr 10;256(5054):243-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, Johns Hopkins University, Baltimore, MD 21218.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1314424" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Chlorides/*pharmacology ; Choline/pharmacology ; Embryo, Nonmammalian/physiology ; Female ; Inositol 1,4,5-Trisphosphate/metabolism ; Inositol Phosphates/*metabolism ; Kinetics ; Lithium/*pharmacology ; Lithium Chloride ; Mesoderm/drug effects/*physiology ; Signal Transduction/drug effects ; Teratogens/*pharmacology ; Xenopus/*embryology
    Print ISSN: 0036-8075
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 99
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    Fast perceptual learning in visual hyperacuity (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-05-15
    Description: In many different spatial discrimination tasks, such as in determining the sign of the offset in a vernier stimulus, the human visual system exhibits hyperacuity by evaluating spatial relations with the precision of a fraction of a photoreceptor's diameter. It is proposed that this impressive performance depends in part on a fast learning process that uses relatively few examples and that occurs at an early processing stage in the visual pathway. This hypothesis is given support by the demonstration that it is possible to synthesize, from a small number of examples of a given task, a simple network that attains the required performance level. Psychophysical experiments agree with some of the key predictions of the model. In particular, fast stimulus-specific learning is found to take place in the human visual system, and this learning does not transfer between two slightly different hyperacuity tasks.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Poggio, T -- Fahle, M -- Edelman, S -- New York, N.Y. -- Science. 1992 May 15;256(5059):1018-21.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge 02139.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1589770" target="_blank"〉PubMed〈/a〉
    Keywords: Algorithms ; Computer Simulation ; Humans ; Kinetics ; Learning/*physiology ; Models, Biological ; Photoreceptor Cells/physiology ; Visual Acuity/*physiology ; Visual Pathways/physiology ; Visual Perception/*physiology
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 100
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    Range of messenger action of calcium ion and inositol 1,4,5-trisphosphate (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-12-11
    Description: The range of messenger action of a point source of Ca2+ or inositol 1,4,5-trisphosphate (IP3) was determined from measurements of their diffusion coefficients in a cytosolic extract from Xenopus laevis oocytes. The diffusion coefficient (D) of [3H]IP3 injected into an extract was 283 microns 2/s. D for Ca2+ increased from 13 to 65 microns 2/s when the free calcium concentration was raised from about 90 nM to 1 microM. The slow diffusion of Ca2+ in the physiologic concentration range results from its binding to slowly mobile or immobile buffers. The calculated effective ranges of free Ca2+ before it is buffered, buffered Ca2+, and IP3 determined from their diffusion coefficients and lifetimes were 0.1 micron, 5 microns, and 24 microns, respectively. Thus, for a transient point source of messenger in cells smaller than 20 microns, IP3 is a global messenger, whereas Ca2+ acts in restricted domains.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Allbritton, N L -- Meyer, T -- Stryer, L -- 5F32AI0814203/AI/NIAID NIH HHS/ -- MH45324/MH/NIMH NIH HHS/ -- New York, N.Y. -- Science. 1992 Dec 11;258(5089):1812-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cell Biology, Stanford University, CA 94305.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1465619" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Calcium/*metabolism ; Calcium-Transporting ATPases/antagonists & inhibitors ; Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone/pharmacology ; Chromatography, High Pressure Liquid ; Cytosol/metabolism ; Diffusion ; Inositol 1,4,5-Trisphosphate/*metabolism ; Kinetics ; Oocytes/drug effects/*metabolism ; *Second Messenger Systems ; *Signal Transduction ; Terpenes/pharmacology ; Thapsigargin ; Time Factors ; Xenopus laevis
    Print ISSN: 0036-8075
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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