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  • Kinetics  (239)
  • Models, Molecular  (214)
  • American Association for the Advancement of Science (AAAS)  (439)
  • American Chemical Society (ACS)
  • 1990-1994  (439)
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  • American Association for the Advancement of Science (AAAS)  (439)
  • American Chemical Society (ACS)
  • Springer  (25)
  • Wiley-Blackwell  (21)
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  • 1
    Publication Date: 1994-06-24
    Description: Two ternary complexes of rat DNA polymerase beta (pol beta), a DNA template-primer, and dideoxycytidine triphosphate (ddCTP) have been determined at 2.9 A and 3.6 A resolution, respectively. ddCTP is the triphosphate of dideoxycytidine (ddC), a nucleoside analog that targets the reverse transcriptase of human immunodeficiency virus (HIV) and is at present used to treat AIDS. Although crystals of the two complexes belong to different space groups, the structures are similar, suggesting that the polymerase-DNA-ddCTP interactions are not affected by crystal packing forces. In the pol beta active site, the attacking 3'-OH of the elongating primer, the ddCTP phosphates, and two Mg2+ ions are all clustered around Asp190, Asp192, and Asp256. Two of these residues, Asp190 and Asp256, are present in the amino acid sequences of all polymerases so far studied and are also spatially similar in the four polymerases--the Klenow fragment of Escherichia coli DNA polymerase I, HIV-1 reverse transcriptase, T7 RNA polymerase, and rat DNA pol beta--whose crystal structures are now known. A two-metal ion mechanism is described for the nucleotidyl transfer reaction and may apply to all polymerases. In the ternary complex structures analyzed, pol beta binds to the DNA template-primer in a different manner from that recently proposed for other polymerase-DNA models.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pelletier, H -- Sawaya, M R -- Kumar, A -- Wilson, S H -- Kraut, J -- CA17374/CA/NCI NIH HHS/ -- ES06839/ES/NIEHS NIH HHS/ -- GM10928/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Jun 24;264(5167):1891-903.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of California, San Diego 92093-0317.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7516580" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Base Sequence ; Binding Sites ; Crystallization ; Crystallography, X-Ray ; DNA/chemistry/metabolism ; DNA Polymerase I/*chemistry/metabolism ; DNA Primers/*chemistry/metabolism ; DNA-Directed RNA Polymerases/chemistry/metabolism ; Deoxycytosine Nucleotides/*chemistry/metabolism ; Dideoxynucleotides ; HIV Reverse Transcriptase ; Humans ; Hydrogen Bonding ; Models, Molecular ; Molecular Sequence Data ; RNA-Directed DNA Polymerase/chemistry/metabolism ; Rats ; Recombinant Proteins ; Templates, Genetic ; Thymine Nucleotides/chemistry/metabolism ; Viral Proteins ; Zidovudine/analogs & derivatives/chemistry/metabolism
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  • 2
    Publication Date: 1994-04-01
    Description: The crystal structure of a ternary protein complex has been determined at 2.4 angstrom resolution. The complex is composed of three electron transfer proteins from Paracoccus denitrificans, the quinoprotein methylamine dehydrogenase, the blue copper protein amicyanin, and the cytochrome c551i. The central region of the c551i is folded similarly to several small bacterial c-type cytochromes; there is a 45-residue extension at the amino terminus and a 25-residue extension at the carboxyl terminus. The methylamine dehydrogenase-amicyanin interface is largely hydrophobic, whereas the amicyanin-cytochrome interface is more polar, with several charged groups present on each surface. Analysis of the simplest electron transfer pathways between the redox partners points out the importance of other factors such as energetics in determining the electron transfer rates.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chen, L -- Durley, R C -- Mathews, F S -- Davidson, V L -- GM41574/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Apr 1;264(5155):86-90.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Molecular Biophysics, 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/8140419" target="_blank"〉PubMed〈/a〉
    Keywords: Bacterial Proteins/*chemistry/metabolism ; Computer Graphics ; Cytochrome c Group/*chemistry/metabolism ; Electron Transport ; Hydrogen Bonding ; *Indolequinones ; Models, Molecular ; Oxidation-Reduction ; Oxidoreductases Acting on CH-NH Group Donors/*chemistry/metabolism ; Paracoccus denitrificans/*chemistry/enzymology ; Protein Conformation ; Protein Folding ; Protein Structure, Secondary ; Quinones/chemistry/metabolism ; Software ; Tryptophan/analogs & derivatives/chemistry/metabolism
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  • 3
    Publication Date: 1994-02-04
    Description: The three-dimensional structure of a catalytic antibody (1F7) with chorismate mutase activity has been determined to 3.0 A resolution as a complex with a transition state analog. The structural data suggest that the antibody stabilizes the same conformationally restricted pericyclic transition state as occurs in the uncatalyzed reaction. Overall shape and charge complementarity between the combining site and the transition state analog dictate preferential binding of the correct substrate enantiomer in a conformation appropriate for reaction. Comparison with the structure of a chorismate mutase enzyme indicates an overall similarity between the catalytic mechanism employed by the two proteins. Differences in the number of specific interactions available for restricting the rotational degrees of freedom in the transition state, and the lack of multiple electrostatic interactions that might stabilize charge separation in this highly polarized metastable species, are likely to account for the observed 10(4) times lower activity of the antibody relative to that of the natural enzymes that catalyze this reaction. The structure of the 1F7 Fab'-hapten complex provides confirmation that the properties of an antibody catalyst faithfully reflect the design of the transition state analog.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Haynes, M R -- Stura, E A -- Hilvert, D -- Wilson, I A -- AI-23498/AI/NIAID NIH HHS/ -- GM-38273/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Feb 4;263(5147):646-52.〈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/8303271" target="_blank"〉PubMed〈/a〉
    Keywords: Antibodies, Catalytic/*chemistry/metabolism ; Bacillus subtilis/enzymology ; Binding Sites ; Binding Sites, Antibody ; Catalysis ; Chorismate Mutase/*chemistry/metabolism ; Chorismic Acid/metabolism ; Crystallization ; Haptens ; Hydrogen Bonding ; Immunoglobulin Fab Fragments/metabolism ; Models, Molecular ; Thermodynamics
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  • 4
    Publication Date: 1994-07-01
    Description: Here it is shown, with the use of protein-protein photocrosslinking, that the carboxyl-terminal region of the alpha subunit of RNA polymerase (RNAP) is in direct physical proximity to the activating region of the catabolite gene activator protein (CAP) in the ternary complex of the lac promoter, RNAP, and CAP. These results strongly support the proposal that transcription activation by CAP involves protein-protein contact between the carboxyl-terminal region of the alpha subunit and the activating region of CAP.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chen, Y -- Ebright, Y W -- Ebright, R H -- GM41376/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Jul 1;265(5168):90-2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Rutgers University, New Brunswick, NJ 08855.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8016656" target="_blank"〉PubMed〈/a〉
    Keywords: Azides/metabolism ; Cross-Linking Reagents ; Crystallography, X-Ray ; Cyclic AMP Receptor Protein/chemistry/*metabolism ; DNA-Directed RNA Polymerases/chemistry/*metabolism ; Lac Operon ; Models, Molecular ; *Promoter Regions, Genetic ; Pyridines/metabolism ; *Transcriptional Activation
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  • 5
    Publication Date: 1994-10-21
    Description: The structure of the heterodimeric flavocytochrome c sulfide dehydrogenase from Chromatium vinosum was determined at a resolution of 2.53 angstroms. It contains a glutathione reductase-like flavin-binding subunit and a diheme cytochrome subunit. The diheme cytochrome folds as two domains, each resembling mitochondrial cytochrome c, and has an unusual interpropionic acid linkage joining the two heme groups in the interior of the subunit. The active site of the flavoprotein subunit contains a catalytically important disulfide bridge located above the pyrimidine portion of the flavin ring. A tryptophan, threonine, or tyrosine side chain may provide a partial conduit for electron transfer to one of the heme groups located 10 angstroms from the flavin.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chen, Z W -- Koh, M -- Van Driessche, G -- Van Beeumen, J J -- Bartsch, R G -- Meyer, T E -- Cusanovich, M A -- Mathews, F S -- GM-20530/GM/NIGMS NIH HHS/ -- GM-21277/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Oct 21;266(5184):430-2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Molecular Biophysics, 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/7939681" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Chromatium/*enzymology ; Computer Graphics ; Crystallography, X-Ray ; Cytochrome c Group/*chemistry ; Electron Transport ; Flavin-Adenine Dinucleotide/metabolism ; Hydrogen Bonding ; Models, Molecular ; Oxidoreductases/*chemistry ; Protein Conformation ; Protein Structure, Secondary
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  • 6
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-05-20
    Description: A predictive rule for protein folding is presented that involves two recurrent glycine-based motifs that cap the carboxyl termini of alpha helices. In proteins, helices that terminated in glycine residues were found predominantly in one of these two motifs. These glycine structures had a characteristic pattern of polar and apolar residues. Visual inspection of known helical sequences was sufficient to distinguish the two motifs from each other and from internal glycines that fail to terminate helices. These glycine motifs--in which the local sequence selects between available structures--represent an example of a stereochemical rule for protein folding.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Aurora, R -- Srinivasan, R -- Rose, G D -- GM 29458/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 May 20;264(5162):1126-30.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Molecular Biophysics, 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/8178170" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Glycine/*chemistry ; Hydrogen Bonding ; Models, Molecular ; Molecular Sequence Data ; Mutation ; Oligopeptides/chemistry ; *Protein Folding ; *Protein Structure, Secondary
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  • 7
    Publication Date: 1994-06-03
    Description: Multi-wavelength anomalous diffraction (MAD) has been used to determine the structure of the regulatory enzyme of de novo synthesis of purine nucleotides, glutamine 5-phosphoribosyl-1-pyrophosphate (PRPP) amidotransferase, from Bacillus subtilis. This allosteric enzyme, a 200-kilodalton tetramer, is subject to end product regulation by purine nucleotides. The metalloenzyme from B. subtilis is a paradigm for the higher eukaryotic enzymes, which have been refractory to isolation in stable form. The two folding domains of the polypeptide are correlated with functional domains for glutamine binding and for transfer of ammonia to the substrate PRPP. Eight molecules of the feedback inhibitor adenosine monophosphate (AMP) are bound to the tetrameric enzyme in two types of binding sites: the PRPP catalytic site of each subunit and an unusual regulatory site that is immediately adjacent to each active site but is between subunits. An oxygen-sensitive [4Fe-4S] cluster in each subunit is proposed to regulate protein turnover in vivo and is distant from the catalytic site. Oxygen sensitivity of the cluster is diminished by AMP, which blocks a channel through the protein to the cluster. The structure is representative of both glutamine amidotransferases and phosphoribosyltransferases.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Smith, J L -- Zaluzec, E J -- Wery, J P -- Niu, L -- Switzer, R L -- Zalkin, H -- Satow, Y -- DK-42303/DK/NIDDK NIH HHS/ -- GM-24658/GM/NIGMS NIH HHS/ -- R37 DK042303/DK/NIDDK NIH HHS/ -- New York, N.Y. -- Science. 1994 Jun 3;264(5164):1427-33.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Sciences, Purdue University, West Lafayette, IN 47907.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8197456" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Monophosphate/metabolism ; Allosteric Regulation ; Amidophosphoribosyltransferase/*chemistry/metabolism ; Amino Acid Sequence ; Animals ; Bacillus subtilis/*enzymology ; Binding Sites ; Computer Graphics ; Crystallography, X-Ray ; Humans ; Models, Molecular ; Molecular Sequence Data ; Oxygen/pharmacology ; Protein Folding ; Protein Structure, Secondary ; Saccharomyces cerevisiae
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  • 8
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    American Association for the Advancement of Science (AAAS)
    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
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  • 9
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-03-11
    Description: Protein tyrosine phosphatases (PTPs) constitute a family of receptor-like and cytoplasmic signal transducing enzymes that catalyze the dephosphorylation of phosphotyrosine residues and are characterized by homologous catalytic domains. The crystal structure of a representative member of this family, the 37-kilodalton form (residues 1 to 321) of PTP1B, has been determined at 2.8 A resolution. The enzyme consists of a single domain with the catalytic site located at the base of a shallow cleft. The phosphate recognition site is created from a loop that is located at the amino-terminus of an alpha helix. This site is formed from an 11-residue sequence motif that is diagnostic of PTPs and the dual specificity phosphatases, and that contains the catalytically essential cysteine and arginine residues. The position of the invariant cysteine residue within the phosphate binding site is consistent with its role as a nucleophile in the catalytic reaction. The structure of PTP1B should serve as a model for other members of the PTP family and as a framework for understanding the mechanism of tyrosine dephosphorylation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Barford, D -- Flint, A J -- Tonks, N K -- CA53840/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1994 Mar 11;263(5152):1397-404.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉W.M. Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, NY 11724.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8128219" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Binding Sites ; Computer Graphics ; Crystallography, X-Ray ; Humans ; Models, Molecular ; Molecular Sequence Data ; Phosphates/metabolism ; Protein Conformation ; Protein Folding ; Protein Structure, Secondary ; Protein Tyrosine Phosphatases/*chemistry/isolation & purification/metabolism ; Substrate Specificity ; Tungsten Compounds/metabolism
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  • 10
    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
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  • 11
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    American Association for the Advancement of Science (AAAS)
    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
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  • 12
    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
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  • 13
    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
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  • 14
    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
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  • 15
    Publication Date: 1994-03-04
    Description: The enzyme acetylcholinesterase generates a strong electrostatic field that can attract the cationic substrate acetylcholine to the active site. However, the long and narrow active site gorge seems inconsistent with the enzyme's high catalytic rate. A molecular dynamics simulation of acetylcholinesterase in water reveals the transient opening of a short channel, large enough to pass a water molecule, through a thin wall of the active site near tryptophan-84. This simulation suggests that substrate, products, or solvent could move through this "back door," in addition to the entrance revealed by the crystallographic structure. Electrostatic calculations show a strong field at the back door, oriented to attract the substrate and the reaction product choline and to repel the other reaction product, acetate. Analysis of the open back door conformation suggests a mutation that could seal the back door and thus test the hypothesis that thermal motion of this enzyme may open multiple routes of access to its active site.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gilson, M K -- Straatsma, T P -- McCammon, J A -- Ripoll, D R -- Faerman, C H -- Axelsen, P H -- Silman, I -- Sussman, J L -- New York, N.Y. -- Science. 1994 Mar 4;263(5151):1276-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of Houston, TX 77204-5641.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8122110" target="_blank"〉PubMed〈/a〉
    Keywords: Acetylcholine/metabolism ; Acetylcholinesterase/*chemistry/metabolism ; Binding Sites ; Catalysis ; Choline/metabolism ; Computer Simulation ; Crystallography, X-Ray ; Electrochemistry ; Models, Molecular ; *Protein Conformation
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  • 16
    Publication Date: 1994-06-10
    Description: Specific protein-ligand interactions are critical for cellular function, and most proteins select their partners with sharp discrimination. However, the oligopeptide-binding protein of Salmonella typhimurium (OppA) binds peptides of two to five amino acid residues without regard to sequence. The crystal structure of OppA reveals a three-domain organization, unlike other periplasmic binding proteins. In OppA-peptide complexes, the ligands are completely enclosed in the protein interior, a mode of binding that normally imposes tight specificity. The protein fulfills the hydrogen bonding and electrostatic potential of the ligand main chain and accommodates the peptide side chains in voluminous hydrated cavities.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tame, J R -- Murshudov, G N -- Dodson, E J -- Neil, T K -- Dodson, G G -- Higgins, C F -- Wilkinson, A J -- New York, N.Y. -- Science. 1994 Jun 10;264(5165):1578-81.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of York, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8202710" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Bacterial Proteins/chemistry/*metabolism ; Binding Sites ; Carrier Proteins/chemistry/*metabolism ; Crystallography, X-Ray ; Hydrogen Bonding ; Ligands ; Lipoproteins/chemistry/*metabolism ; Models, Molecular ; Molecular Sequence Data ; Molecular Weight ; Oligopeptides/chemistry/*metabolism ; Protein Conformation ; Protein Structure, Secondary
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  • 17
    Publication Date: 1994-09-30
    Description: Nucleotide sequence information derived from DNA segments of the human and other genomes is accumulating rapidly. However, it frequently proves difficult to use such short DNA segments to identify clones in genomic libraries or fragments in blots of the whole genome or for in situ analysis of chromosomes. Oligonucleotide probes, consisting of two target-complementary segments, connected by a linker sequence, were designed. Upon recognition of the specific nucleic acid molecule the ends of the probes were joined through the action of a ligase, creating circular DNA molecules catenated to the target sequence. These probes thus provide highly specific detection with minimal background.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nilsson, M -- Malmgren, H -- Samiotaki, M -- Kwiatkowski, M -- Chowdhary, B P -- Landegren, U -- New York, N.Y. -- Science. 1994 Sep 30;265(5181):2085-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Beijer Laboratory, Department of Medical Genetics, Biomedical Center, Uppsala, Sweden.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7522346" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Cells, Cultured ; Chromosomes, Human, Pair 12 ; Cystic Fibrosis Transmembrane Conductance Regulator ; DNA/*analysis ; DNA, Circular/*analysis ; Genetic Vectors ; Humans ; In Situ Hybridization ; Lymphocytes ; Membrane Proteins/genetics ; Models, Molecular ; Molecular Sequence Data ; Nucleic Acid Conformation ; *Oligonucleotide Probes/chemistry ; Repetitive Sequences, Nucleic Acid ; Templates, Genetic
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  • 18
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    Unknown
    American Association for the Advancement of Science (AAAS)
    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
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  • 19
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-03-04
    Description: Physical inclusion of small molecules in larger structural lattices is well known in the crystalline state and is a common feature of the chemistry of zeolites. In the liquid state, a variety of synthetic macrocyclic molecules are available to complex and contain smaller guest species. An alternative strategy for binding is explored: assembly of cavity-forming structures from small subunits. Encapsulation of small guest molecules such as methane can be achieved with a synthetic structure that assembles reversibly through hydrogen bonding.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Branda, N -- Wyler, R -- Rebek, J Jr -- New York, N.Y. -- Science. 1994 Mar 4;263(5151):1267-8.〈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/8122107" target="_blank"〉PubMed〈/a〉
    Keywords: Benzyl Compounds/chemistry ; Chemistry, Physical ; Chloroform ; Hydrogen Bonding ; Imidazoles/chemistry ; Magnetic Resonance Spectroscopy ; Methane/*chemistry ; Models, Molecular ; Molecular Conformation ; Molecular Structure ; Physicochemical Phenomena ; Polymers/*chemistry ; Temperature ; Thermodynamics
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  • 20
    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
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  • 21
    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
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  • 22
    Publication Date: 1994-11-04
    Description: The three-dimensional structure of a ternary complex of the purine repressor, PurR, bound to both its corepressor, hypoxanthine, and the 16-base pair purF operator site has been solved at 2.7 A resolution by x-ray crystallography. The bipartite structure of PurR consists of an amino-terminal DNA-binding domain and a larger carboxyl-terminal corepressor binding and dimerization domain that is similar to that of the bacterial periplasmic binding proteins. The DNA-binding domain contains a helix-turn-helix motif that makes base-specific contacts in the major groove of the DNA. Base contacts are also made by residues of symmetry-related alpha helices, the "hinge" helices, which bind deeply in the minor groove. Critical to hinge helix-minor groove binding is the intercalation of the side chains of Leu54 and its symmetry-related mate, Leu54', into the central CpG-base pair step. These residues thereby act as "leucine levers" to pry open the minor groove and kink the purF operator by 45 degrees.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schumacher, M A -- Choi, K Y -- Zalkin, H -- Brennan, R G -- GM 24658/GM/NIGMS NIH HHS/ -- GM 49244/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Nov 4;266(5186):763-70.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Molecular Biology, Oregon Health Sciences University, Portland 97201-3098.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7973627" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Bacterial Proteins/*chemistry/genetics/metabolism ; Base Sequence ; Binding Sites ; Computer Graphics ; Crystallography, X-Ray ; DNA/chemistry/*metabolism ; DNA-Binding Proteins/*chemistry/genetics/metabolism ; *Escherichia coli Proteins ; Hydrogen Bonding ; Hypoxanthine ; Hypoxanthines/metabolism ; Lac Repressors ; Models, Molecular ; Molecular Sequence Data ; Nucleic Acid Conformation ; *Operator Regions, Genetic ; Protein Conformation ; Protein Structure, Secondary ; Repressor Proteins/*chemistry/genetics/metabolism
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  • 23
    Publication Date: 1994-07-22
    Description: Cellulose is the major polysaccharide of plants where it plays a predominantly structural role. A variety of highly specialized microorganisms have evolved to produce enzymes that either synergistically or in complexes can carry out the complete hydrolysis of cellulose. The structure of the major cellobiohydrolase, CBHI, of the potent cellulolytic fungus Trichoderma reesei has been determined and refined to 1.8 angstrom resolution. The molecule contains a 40 angstrom long active site tunnel that may account for many of the previously poorly understood macroscopic properties of the enzyme and its interaction with solid cellulose. The active site residues were identified by solving the structure of the enzyme complexed with an oligosaccharide, o-iodobenzyl-1-thio-beta-cellobioside. The three-dimensional structure is very similar to a family of bacterial beta-glucanases with the main-chain topology of the plant legume lectins.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Divne, C -- Stahlberg, J -- Reinikainen, T -- Ruohonen, L -- Pettersson, G -- Knowles, J K -- Teeri, T T -- Jones, T A -- New York, N.Y. -- Science. 1994 Jul 22;265(5171):524-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Uppsala University, Sweden.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8036495" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Catalysis ; Cellobiose/analogs & derivatives/chemistry/metabolism ; Cellulose/metabolism ; Cellulose 1,4-beta-Cellobiosidase ; Computer Graphics ; Crystallography, X-Ray ; Glycoside Hydrolases/*chemistry/metabolism ; Hydrogen Bonding ; Iodobenzenes/chemistry/metabolism ; Models, Molecular ; Protein Structure, Secondary ; Trichoderma/*enzymology
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  • 24
    Publication Date: 1994-08-05
    Description: Peptide nucleic acids (PNA) incorporating nucleic acid bases into an achiral polyamide backbone bind to DNA in a sequence-dependent manner. The structure of a PNA-ribonucleic acid (RNA) complex was determined with nuclear magnetic resonance methods. A hexameric PNA formed a 1:1 complex with a complementary RNA that is an antiparallel, right-handed double helix with Watson-Crick base pairing similar to the "A" form structure of RNA duplexes. The achiral PNA backbone assumed a distinct conformation upon binding that differed from previously proposed models and provides a basis for further structure-based design of antisense agents.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Brown, S C -- Thomson, S A -- Veal, J M -- Davis, D G -- New York, N.Y. -- Science. 1994 Aug 5;265(5173):777-80.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Glaxo Research Institute, Research Triangle Park, NC 27709.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7519361" target="_blank"〉PubMed〈/a〉
    Keywords: Magnetic Resonance Spectroscopy ; Models, Molecular ; Nucleic Acid Conformation ; Oligodeoxyribonucleotides/*chemistry ; Peptides/*chemistry ; RNA/*chemistry
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  • 25
    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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  • 26
    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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  • 27
    Publication Date: 1994-12-23
    Description: HIV integrase is the enzyme responsible for inserting the viral DNA into the host chromosome; it is essential for HIV replication. The crystal structure of the catalytically active core domain (residues 50 to 212) of HIV-1 integrase was determined at 2.5 A resolution. The central feature of the structure is a five-stranded beta sheet flanked by helical regions. The overall topology reveals that this domain of integrase belongs to a superfamily of polynucleotidyl transferases that includes ribonuclease H and the Holliday junction resolvase RuvC. The active site region is identified by the position of two of the conserved carboxylate residues essential for catalysis, which are located at similar positions in ribonuclease H. In the crystal, two molecules form a dimer with a extensive solvent-inaccessible interface of 1300 A2 per monomer.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Dyda, F -- Hickman, A B -- Jenkins, T M -- Engelman, A -- Craigie, R -- Davies, D R -- New York, N.Y. -- Science. 1994 Dec 23;266(5193):1981-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Molecular Biology, NIDDK, NIH, Bethesda, MD 20892-0560.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7801124" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Binding Sites ; Crystallization ; Crystallography, X-Ray ; DNA Nucleotidyltransferases/*chemistry ; HIV-1/*enzymology ; Hydrogen Bonding ; Integrases ; Models, Molecular ; Molecular Sequence Data ; Protein Folding ; Protein Structure, Secondary ; Ribonuclease H/chemistry ; Solubility ; Virus Integration
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  • 28
    Publication Date: 1994-12-02
    Description: The pathway of male sexual development in mammals is initiated by SRY, a gene on the short arm of the Y chromosome. Its expression in the differentiating gonadal ridge directs testicular morphogenesis, characterized by elaboration of Mullerian inhibiting substance (MIS) and testosterone. SRY and MIS each belong to conserved gene families that function in the control of growth and differentiation. Structural and biochemical studies of the DNA binding domain of SRY (the HMG box) revealed a protein-DNA interaction consisting of partial side chain intercalation into a widened minor groove. Functional studies of SRY in a cell line from embryonic gonadal ridge demonstrated activation of a gene-regulatory pathway leading to expression of MIS. SRY molecules containing mutations associated with human sex reversal have altered structural interactions with DNA and failed to induce transcription of MIS.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Haqq, C M -- King, C Y -- Ukiyama, E -- Falsafi, S -- Haqq, T N -- Donahoe, P K -- Weiss, M A -- GM51558/GM/NIGMS NIH HHS/ -- HD30812/HD/NICHD NIH HHS/ -- P30HD28138/HD/NICHD NIH HHS/ -- New York, N.Y. -- Science. 1994 Dec 2;266(5190):1494-500.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Pediatric Surgical Research Laboratory, Massachusetts General Hospital, Boston 02114.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7985018" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Anti-Mullerian Hormone ; Base Sequence ; Cell Line ; DNA/metabolism ; DNA-Binding Proteins/chemistry/*genetics/metabolism ; Female ; *Gene Expression Regulation, Developmental ; Genitalia, Male/*embryology ; *Glycoproteins ; Growth Inhibitors/biosynthesis/*genetics ; Humans ; Male ; Models, Biological ; Models, Molecular ; Molecular Sequence Data ; Mullerian Ducts ; *Nuclear Proteins ; Sex Differentiation/*genetics ; Sex-Determining Region Y Protein ; Testicular Hormones/biosynthesis/*genetics ; Transcription Factors/chemistry/*genetics/metabolism
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  • 29
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-10-14
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Carr, C M -- Kim, P S -- New York, N.Y. -- Science. 1994 Oct 14;266(5183):234-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Cambridge, MA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7939658" target="_blank"〉PubMed〈/a〉
    Keywords: Cell Membrane/metabolism/virology ; Endocytosis ; Endosomes/virology ; Hemagglutinin Glycoproteins, Influenza Virus ; Hemagglutinins, Viral/chemistry/*physiology ; Hydrogen-Ion Concentration ; *Membrane Fusion ; Models, Biological ; Models, Molecular ; Orthomyxoviridae/immunology/*physiology ; Protein Conformation ; Viral Envelope Proteins/chemistry/*physiology
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  • 30
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-02-11
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉von Hippel, P H -- GM-15792/GM/NIGMS NIH HHS/ -- GM-29158/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Feb 11;263(5148):769-70.〈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/8303292" target="_blank"〉PubMed〈/a〉
    Keywords: Base Composition ; Base Sequence ; Crystallography, X-Ray ; DNA/chemistry/*metabolism ; DNA-Binding Proteins/chemistry/*metabolism ; Models, Molecular ; Protein Binding ; Protein Conformation ; Thermodynamics
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  • 31
    Publication Date: 1994-04-15
    Description: The most frequently occurring resistance of Gram-negative bacteria against tetracyclines is triggered by drug recognition of the Tet repressor. This causes dissociation of the repressor-operator DNA complex and enables expression of the resistance protein TetA, which is responsible for active efflux of tetracycline. The 2.5 angstrom resolution crystal structure of the homodimeric Tet repressor complexed with tetracycline-magnesium reveals detailed drug recognition. The orientation of the operator-binding helix-turn-helix motifs of the repressor is inverted in comparison with other DNA binding proteins. The repressor-drug complex is unable to interact with DNA because the separation of the DNA binding motifs is 5 angstroms wider than usually observed.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hinrichs, W -- Kisker, C -- Duvel, M -- Muller, A -- Tovar, K -- Hillen, W -- Saenger, W -- New York, N.Y. -- Science. 1994 Apr 15;264(5157):418-20.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institut fur Kristallographie, Freie Universitat Berlin, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8153629" target="_blank"〉PubMed〈/a〉
    Keywords: Antiporters/*chemistry/genetics/metabolism ; Bacterial Proteins/*chemistry/genetics/metabolism ; Crystallography, X-Ray ; DNA, Bacterial/metabolism ; Helix-Loop-Helix Motifs ; Hydrogen Bonding ; Magnesium/chemistry ; Models, Molecular ; Mutation ; Operator Regions, Genetic ; Protein Conformation ; Protein Folding ; Protein Structure, Secondary ; Repressor Proteins/*chemistry/genetics/metabolism ; Tetracycline/*chemistry/metabolism ; *Tetracycline Resistance/genetics
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  • 32
    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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  • 33
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-03-18
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Flam, F -- New York, N.Y. -- Science. 1994 Mar 18;263(5153):1563-4.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8128241" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Models, Molecular ; Protein Conformation ; *Protein Engineering ; *Protein Folding ; Protein Structure, Secondary
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  • 34
    Publication Date: 1994-07-15
    Description: The three-dimensional structure of the oligomerization domain (residues 319 to 360) of the tumor suppressor p53 has been solved by multidimensional heteronuclear magnetic resonance (NMR) spectroscopy. The domain forms a 20-kilodalton symmetric tetramer with a topology made up from a dimer of dimers. The two primary dimers each comprise two antiparallel helices linked by an antiparallel beta sheet. One beta strand and one helix are contributed from each monomer. The interface between the two dimers forming the tetramer is mediated solely by helix-helix contacts. The overall result is a symmetric, four-helix bundle with adjacent helices oriented antiparallel to each other and with the two antiparallel beta sheets located on opposing faces of the molecule. The tetramer is stabilized not only by hydrophobic interactions within the protein core but also by a number of electrostatic interactions. The implications of the structure of the tetramer for the biological function of p53 are discussed.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Clore, G M -- Omichinski, J G -- Sakaguchi, K -- Zambrano, N -- Sakamoto, H -- Appella, E -- Gronenborn, A M -- New York, N.Y. -- Science. 1994 Jul 15;265(5170):386-91.〈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, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8023159" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Computer Graphics ; DNA/chemistry/metabolism ; Genes, p53 ; Macromolecular Substances ; Magnetic Resonance Spectroscopy ; Models, Molecular ; Molecular Sequence Data ; Mutation ; *Protein Conformation ; Protein Structure, Secondary ; Tumor Suppressor Protein p53/*chemistry/genetics/metabolism
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  • 35
    Publication Date: 1994-10-21
    Description: Femtosecond pump-probe experiments reveal the impulsive production of photoproduct in the primary event in vision. The retinal chromophore of rhodopsin was excited with a 35-femtosecond pulse at 500 nanometers, and transient changes in absorption were measured with 10-femtosecond probe pulses. At probe wavelengths within the photo-product absorption band, oscillatory features with a period of 550 femtoseconds (60 wavenumbers) were observed whose phase and amplitude demonstrate that they are the result of nonstationary vibrational motion in the ground state of the photoproduct. The observation of coherent vibrational motion of the photoproduct supports the idea that the primary step in vision is a vibrationally coherent process and that the high quantum yield of the cis--〉trans isomerization in rhodopsin is a consequence of the extreme speed of the excited-state torsional motion.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wang, Q -- Schoenlein, R W -- Peteanu, L A -- Mathies, R A -- Shank, C V -- EY-02051/EY/NEI NIH HHS/ -- New York, N.Y. -- Science. 1994 Oct 21;266(5184):422-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Materials Sciences Division, Lawrence Berkeley Laboratory, University of California, 94720.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7939680" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cattle ; Fourier Analysis ; Isomerism ; *Light ; Models, Molecular ; Photic Stimulation ; Photochemistry ; Rhodopsin/analogs & derivatives/*chemistry ; Spectrum Analysis ; Vision, Ocular/*physiology
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  • 36
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-02-11
    Description: Thermodynamic studies have demonstrated the central importance of a large negative heat capacity change (delta C degree assoc) in site-specific protein-DNA recognition. Dissection of the large negative delta C degree assoc and the entropy change of protein-ligand and protein-DNA complexation provide a thermodynamic signature identifying processes in which local folding is coupled to binding. Estimates of the number of residues that fold on binding obtained from this analysis agree with structural data. Structural comparisons indicate that these local folding transitions create key parts of the protein-DNA interface. The energetic implications of this "induced fit" model for DNA site recognition are considered.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Spolar, R S -- Record, M T Jr -- GM23467/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Feb 11;263(5148):777-84.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of Wisconsin-Madison 53706.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8303294" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Binding Sites ; Crystallography, X-Ray ; DNA/chemistry/*metabolism ; DNA-Binding Proteins/chemistry/*metabolism ; Models, Molecular ; Nucleic Acid Conformation ; Protein Conformation ; *Protein Folding ; Thermodynamics
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  • 37
    Publication Date: 1994-07-15
    Description: The tailspike protein (TSP) of Salmonella typhimurium phage P22 is a part of the apparatus by which the phage attaches to the bacterial host and hydrolyzes the O antigen. It has served as a model system for genetic and biochemical analysis of protein folding. The x-ray structure of a shortened TSP (residues 109 to 666) was determined to a 2.0 angstrom resolution. Each subunit of the homotrimer contains a large parallel beta helix. The interdigitation of the polypeptide chains at the carboxyl termini is important to protrimer formation in the folding pathway and to thermostability of the mature protein.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Steinbacher, S -- Seckler, R -- Miller, S -- Steipe, B -- Huber, R -- Reinemer, P -- New York, N.Y. -- Science. 1994 Jul 15;265(5170):383-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Max-Planck-Institut fur Biochemie, Abteilung Strukturforschung, Martinsried, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8023158" target="_blank"〉PubMed〈/a〉
    Keywords: *Bacteriophage P22 ; Computer Graphics ; Crystallization ; Crystallography, X-Ray ; Glycoside Hydrolases/*chemistry/genetics ; Models, Molecular ; Point Mutation ; Protein Conformation ; *Protein Folding ; Protein Structure, Secondary ; *Protein Structure, Tertiary ; Viral Proteins/*chemistry/genetics ; *Viral Tail Proteins
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  • 38
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    American Association for the Advancement of Science (AAAS)
    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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  • 39
    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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  • 40
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-10-28
    Description: A four-ring tripeptide containing alternating imidazole and pyrrole carboxamides specifically binds six-base pair 5'-(A,T)GCGC(A,T)-3' sites in the minor groove of DNA. The designed peptide has a specificity completely reversed from that of the tripyrrole distamycin, which binds A,T sequences. Structural studies with nuclear magnetic resonance revealed that two peptides bound side-by-side and in an antiparallel orientation in the minor groove. Each of the four imidazoles in the 2:1 ligand-DNA complex recognized a specific guanine amino group in the GCGC core through a hydrogen bond. Targeting a designated four-base pair G.C tract by this synthetic ligand supports the generality of the 2:1 peptide-DNA motif for sequence-specific minor groove recognition of DNA.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Geierstanger, B H -- Mrksich, M -- Dervan, P B -- Wemmer, D E -- GM-27681/GM/NIGMS NIH HHS/ -- GM-43129/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Oct 28;266(5185):646-50.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Graduate Group in Biophysics, University of California, Berkeley 94720.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7939719" target="_blank"〉PubMed〈/a〉
    Keywords: Base Composition ; Base Sequence ; Computer Graphics ; DNA/chemistry/*metabolism ; Drug Design ; Hydrogen Bonding ; Imidazoles/chemical synthesis/*chemistry/metabolism ; Ligands ; Magnetic Resonance Spectroscopy ; Models, Molecular ; Molecular Sequence Data ; Nucleic Acid Conformation ; Oligodeoxyribonucleotides/chemistry/metabolism ; Oligopeptides/chemical synthesis/*chemistry/metabolism ; Protein Conformation ; Pyrroles/chemical synthesis/*chemistry/metabolism
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  • 41
    Publication Date: 1994-04-01
    Description: The crystal structure of a complex between a 24-amino acid peptide from the third variable (V3) loop of human immunodeficiency virus-type 1 (HIV-1) gp 120 and the Fab fragment of a broadly neutralizing antibody (59.1) was determined to 3 angstrom resolution. The tip of the V3 loop containing the Gly-Pro-Gly-Arg-Ala-Phe sequence adopts a double-turn conformation, which may be the basis of its conservation in many HIV-1 isolates. A complete map of the HIV-1 principal neutralizing determinant was constructed by stitching together structures of V3 loop peptides bound to 59.1 and to an isolate-specific (MN) neutralizing antibody (50.1). Structural conservation of the overlapping epitopes suggests that this biologically relevant conformation could be of use in the design of synthetic vaccines and drugs to inhibit HIV-1 entry and virus-related cellular fusion.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ghiara, J B -- Stura, E A -- Stanfield, R L -- Profy, A T -- Wilson, I A -- GM-46192/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Apr 1;264(5155):82-5.〈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/7511253" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Antibodies, Monoclonal/chemistry/immunology ; Antigen-Antibody Complex/*chemistry/immunology ; Antigen-Antibody Reactions ; Computer Graphics ; Crystallography, X-Ray ; Epitopes/chemistry/immunology ; HIV Antibodies/*chemistry/immunology ; HIV Envelope Protein gp120/*chemistry/immunology ; HIV-1/*chemistry/immunology ; Hydrogen Bonding ; Immunoglobulin Fab Fragments/*chemistry/immunology ; Models, Molecular ; Molecular Sequence Data ; Neutralization Tests ; Peptide Fragments/*chemistry/immunology ; Protein Conformation ; Protein Structure, Secondary
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  • 42
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-12-16
    Description: DNA is often bent when complexed with proteins. Understanding the forces responsible for DNA bending would be of fundamental value in exploring the interplay of these macromolecules. A series of experiments was devised to test the hypothesis that proteins with cationic surfaces can induce substantial DNA bending by neutralizing phosphates on one DNA face. Repulsions between phosphates in the remaining anionic helix are predicted to result in an unbalanced compression force acting to deform the DNA toward the protein. This hypothesis is supported by the results of electrophoretic experiments in which DNA spontaneously bends when one helical face is partially modified by incorporation of neutral phosphate analogs. Phasing with respect to a site of intrinsic DNA curvature (hexadeoxyadenylate tract) permits estimation of the electrostatic bend angle, and demonstrates that such modified DNAs are deformed toward the neutralized surface, as predicted. Similar model systems may be useful in exploring the extent to which phosphate neutralization can account for DNA bending by particular proteins.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Strauss, J K -- Maher, L J 3rd -- GM47814/GM/NIGMS NIH HHS/ -- P30 CA36727-08/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1994 Dec 16;266(5192):1829-34.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha 68198-6805.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7997878" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Cations/chemistry ; DNA/*chemistry ; DNA-Binding Proteins/chemistry ; Electrochemistry ; Electrophoresis, Polyacrylamide Gel ; Models, Molecular ; Molecular Sequence Data ; *Nucleic Acid Conformation ; Nucleosomes/chemistry ; Oligodeoxyribonucleotides ; Organophosphorus Compounds/chemistry ; Phosphates/*chemistry ; Thermodynamics
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  • 43
    Publication Date: 1994-08-19
    Description: The three-dimensional structure of an unusually active hydrolytic antibody with a phosphonate transition state analog (hapten) bound to the active site has been solved to 2.5 A resolution. The antibody (17E8) catalyzes the hydrolysis of norleucine and methionine phenyl esters and is selective for amino acid esters that have the natural alpha-carbon L configuration. A plot of the pH-dependence of the antibody-catalyzed reaction is bell-shaped with an activity maximum at pH 9.5; experiments on mechanism lend support to the formation of a covalent acyl-antibody intermediate. The structural and kinetic data are complementary and support a hydrolytic mechanism for the antibody that is remarkably similar to that of the serine proteases. The antibody active site contains a Ser-His dyad structure proximal to the phosphorous atom of the bound hapten that resembles two of the three components of the Ser-His-Asp catalytic triad of serine proteases. The antibody active site also contains a Lys residue to stabilize oxyanion formation, and a hydrophobic binding pocket for specific substrate recognition of norleucine and methionine side chains. The structure identifies active site residues that mediate catalysis and suggests specific mutations that may improve the catalytic efficiency of the antibody. This high resolution structure of a catalytic antibody-hapten complex shows that antibodies can converge on active site structures that have arisen through natural enzyme evolution.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zhou, G W -- Guo, J -- Huang, W -- Fletterick, R J -- Scanlan, T S -- DK39304/DK/NIDDK NIH HHS/ -- New York, N.Y. -- Science. 1994 Aug 19;265(5175):1059-64.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Biophysics, University of California, San Francisco 94143-0448.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8066444" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Antibodies, Catalytic/*chemistry/immunology/metabolism ; Binding Sites ; Computer Graphics ; Crystallization ; Crystallography, X-Ray ; Haptens/metabolism ; Hydrogen Bonding ; Hydrogen-Ion Concentration ; Hydrolysis ; Models, Molecular ; Molecular Sequence Data ; Protein Conformation ; Serine Endopeptidases/*chemistry/metabolism
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  • 44
    Publication Date: 1994-01-21
    Description: Collagenase is a zinc-dependent endoproteinase and is a member of the matrix metalloproteinase (MMP) family of enzymes. The MMPs participate in connective tissue remodeling events and aberrant regulation has been associated with several pathologies. The 2.4 angstrom resolution structure of the inhibited enzyme revealed that, in addition to the catalytic zinc, there is a second zinc ion and a calcium ion which play a major role in stabilizing the tertiary structure of collagenase. Despite scant sequence homology, collagenase shares structural homology with two other endoproteinases, bacterial thermolysin and crayfish astacin. The detailed description of protein-inhibitor interactions present in the structure will aid in the design of compounds that selectively inhibit individual members of the MMP family. Such inhibitors will be useful in examining the function of MMPs in pathological processes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lovejoy, B -- Cleasby, A -- Hassell, A M -- Longley, K -- Luther, M A -- Weigl, D -- McGeehan, G -- McElroy, A B -- Drewry, D -- Lambert, M H -- New York, N.Y. -- Science. 1994 Jan 21;263(5145):375-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Glaxo Research Institute, Research Triangle Park, NC 27709.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8278810" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Binding Sites ; Calcium/metabolism ; Collagenases/*chemistry/metabolism ; Computer Graphics ; Crystallography, X-Ray ; Humans ; Hydrogen Bonding ; Matrix Metalloproteinase 8 ; Matrix Metalloproteinase Inhibitors ; Metalloendopeptidases/chemistry ; Models, Molecular ; Molecular Sequence Data ; Protein Structure, Secondary ; Protein Structure, Tertiary ; Thermolysin/chemistry ; Zinc/metabolism
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  • 45
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-08-12
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Taubes, G -- New York, N.Y. -- Science. 1994 Aug 12;265(5174):884-6.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8052844" target="_blank"〉PubMed〈/a〉
    Keywords: Computer Graphics ; *Computer Simulation ; Drug Design ; Models, Molecular ; User-Computer Interface
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  • 46
    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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  • 47
    Publication Date: 1994-12-23
    Description: A synthetic combinatorial library containing 52,128,400 D-amino acid hexapeptides was used to identify a ligand for the mu opioid receptor. The peptide, Ac-rfwink-NH2, bears no resemblance to any known opioid peptide. Simulations using molecular dynamics, however, showed that three amino acid moieties have the same spatial orientation as the corresponding pharmacophoric groups of the opioid peptide PLO17. Ac-rfwink-NH2 was shown to be a potent agonist at the mu receptor and induced long-lasting analgesia in mice. Analgesia produced by intraperitoneally administered Ac-rfwink-NH2 was blocked by intracerebroventricular administration of naloxone, demonstrating that this peptide may cross the blood-brain barrier.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Dooley, C T -- Chung, N N -- Wilkes, B C -- Schiller, P W -- Bidlack, J M -- Pasternak, G W -- Houghten, R A -- DA-000138/DA/NIDA NIH HHS/ -- DA-02615/DA/NIDA NIH HHS/ -- DA-03742/DA/NIDA NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1994 Dec 23;266(5193):2019-22.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Torrey Pines Institute for Molecular Studies, San Diego, CA 92121.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7801131" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Analgesics/chemistry/metabolism/*pharmacology ; Animals ; Brain/metabolism ; Dose-Response Relationship, Drug ; Endorphins/pharmacology ; Enkephalin, Ala(2)-MePhe(4)-Gly(5)- ; Enkephalin, D-Penicillamine (2,5)- ; Enkephalins/metabolism ; Guinea Pigs ; Injections, Intraventricular ; Male ; Mice ; Models, Molecular ; Molecular Sequence Data ; Naloxone/administration & dosage/pharmacology ; Opioid Peptides/chemistry/metabolism/*pharmacology ; Pain Measurement ; Protein Conformation ; Rats ; Receptors, Opioid, mu/agonists/metabolism ; Stereoisomerism
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  • 48
    Publication Date: 1994-12-09
    Description: The crystal structure of a 27-kilodalton methylcobalamin-containing fragment of methionine synthase from Escherichia coli was determined at 3.0 A resolution. This structure depicts cobalamin-protein interactions and reveals that the corrin macrocycle lies between a helical amino-terminal domain and an alpha/beta carboxyl-terminal domain that is a variant of the Rossmann fold. Methylcobalamin undergoes a conformational change on binding the protein; the dimethylbenzimidazole group, which is coordinated to the cobalt in the free cofactor, moves away from the corrin and is replaced by a histidine contributed by the protein. The sequence Asp-X-His-X-X-Gly, which contains this histidine ligand, is conserved in the adenosylcobalamin-dependent enzymes methylmalonyl-coenzyme A mutase and glutamate mutase, suggesting that displacement of the dimethylbenzimidazole will be a feature common to many cobalamin-binding proteins. Thus the cobalt ligand, His759, and the neighboring residues Asp757 and Ser810, may form a catalytic quartet, Co-His-Asp-Ser, that modulates the reactivity of the B12 prosthetic group in methionine synthase.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Drennan, C L -- Huang, S -- Drummond, J T -- Matthews, R G -- Lidwig, M L -- GM08570/GM/NIGMS NIH HHS/ -- GM16429/GM/NIGMS NIH HHS/ -- GM24908/GM/NIGMS NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1994 Dec 9;266(5191):1669-74.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Biophysics Research Division, University of Michigan, Ann Arbor 48109-1055.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7992050" target="_blank"〉PubMed〈/a〉
    Keywords: 5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase/*chemistry/metabolism ; Amino Acid Isomerases/chemistry ; Amino Acid Sequence ; Benzimidazoles ; Catalysis ; Computer Graphics ; Crystallography, X-Ray ; Electron Spin Resonance Spectroscopy ; Escherichia coli/*enzymology ; Histidine/metabolism ; *Intramolecular Transferases ; Ligands ; Methylation ; Methylmalonyl-CoA Mutase/chemistry ; Models, Molecular ; Molecular Sequence Data ; Protein Conformation ; Protein Folding ; Protein Structure, Secondary ; Vitamin B 12/*analogs & derivatives/chemistry/metabolism
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  • 49
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-12-23
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉O'Brien, C -- New York, N.Y. -- Science. 1994 Dec 23;266(5193):1946.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7801119" target="_blank"〉PubMed〈/a〉
    Keywords: Antiviral Agents/pharmacology ; Binding Sites ; Crystallization ; Crystallography, X-Ray ; DNA Nucleotidyltransferases/antagonists & inhibitors/*chemistry/metabolism ; DNA-Binding Proteins/metabolism ; Drug Design ; HIV-1/drug effects/*enzymology ; Integrases ; Models, Molecular ; Virus Integration
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  • 50
    Publication Date: 1994-10-21
    Description: The molecular structure of the D-alanine:D-alanine ligase of the ddlB gene of Escherichia coli, co-crystallized with an S,R-methylphosphinate and adenosine triphosphate, was determined by x-ray diffraction to a resolution of 2.3 angstroms. A catalytic mechanism for the ligation of two D-alanine substrates is proposed in which a helix dipole and a hydrogen-bonded triad of tyrosine, serine, and glutamic acid assist binding and deprotonation steps. From sequence comparison, it is proposed that a different triad exists in a recently discovered D-alanine:D-lactate ligase (VanA) present in vancomycin-resistant enterococci. A molecular mechanism for the altered specificity of VanA is suggested.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fan, C -- Moews, P C -- Walsh, C T -- Knox, J R -- 1RO1-AI-34330/AI/NIAID NIH HHS/ -- GM-49338/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Oct 21;266(5184):439-43.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular and Cell Biology, University of Connecticut, Storrs 06269-3125.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7939684" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Diphosphate/chemistry/metabolism ; Amino Acid Sequence ; Bacterial Proteins/chemistry ; Binding Sites ; *Carbon-Oxygen Ligases ; Computer Graphics ; Crystallography, X-Ray ; Dipeptides/biosynthesis ; Drug Resistance, Microbial ; Escherichia coli/drug effects/*enzymology ; Hydrogen Bonding ; Ligases/chemistry ; Models, Molecular ; Molecular Sequence Data ; Molecular Structure ; Peptide Synthases/*chemistry/genetics/metabolism ; Protein Structure, Secondary ; Protein Structure, Tertiary ; Substrate Specificity ; Vancomycin/*pharmacology
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  • 51
    Publication Date: 1994-01-21
    Description: The structure of the 52-amino acid DNA-binding domain of the prokaryotic Hin recombinase, complexed with a DNA recombination half-site, has been solved by x-ray crystallography at 2.3 angstrom resolution. The Hin domain consists of a three-alpha-helix bundle, with the carboxyl-terminal helix inserted into the major groove of DNA, and two flanking extended polypeptide chains that contact bases in the minor groove. The overall structure displays features resembling both a prototypical bacterial helix-turn-helix and the eukaryotic homeodomain, and in many respects is an intermediate between these two DNA-binding motifs. In addition, a new structural motif is seen: the six-amino acid carboxyl-terminal peptide of the Hin domain runs along the minor groove at the edge of the recombination site, with the peptide backbone facing the floor of the groove and side chains extending away toward the exterior. The x-ray structure provides an almost complete explanation for DNA mutant binding studies in the Hin system and for DNA specificity observed in the Hin-related family of DNA invertases.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Feng, J A -- Johnson, R C -- Dickerson, R E -- GM-31299/GM/NIGMS NIH HHS/ -- GM-38509/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Jan 21;263(5145):348-55.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Molecular Biology Institute, University of California, Los Angeles 90024.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8278807" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Base Composition ; Base Sequence ; Binding Sites ; Computer Graphics ; Crystallography, X-Ray ; DNA/chemistry/*metabolism ; DNA Nucleotidyltransferases/chemistry/*metabolism ; Helix-Loop-Helix Motifs ; Hydrogen Bonding ; Models, Molecular ; Molecular Sequence Data ; Nucleic Acid Conformation ; Oligodeoxyribonucleotides/chemistry/metabolism ; Protein Conformation ; Protein Folding ; Protein Structure, Secondary ; *Recombination, Genetic
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  • 52
    Publication Date: 1994-12-16
    Description: The three-dimensional structure of a Staphylococcus aureus superantigen, toxic shock syndrome toxin-1 (TSST-1), complexed with a human class II major histocompatibility molecule (DR1), was determined by x-ray crystallography. The TSST-1 binding site on DR1 overlaps that of the superantigen S. aureus enterotoxin B (SEB), but the two binding modes differ. Whereas SEB binds primarily off one edge of the peptide binding site of DR1, TSST-1 extends over almost one-half of the binding site and contacts both the flanking alpha helices of the histocompatibility antigen and the bound peptide. This difference suggests that the T cell receptor (TCR) would bind to TSST-1:DR1 very differently than to DR1:peptide or SEB:DR1. It also suggests that TSST-1 binding may be dependent on the peptide, though less so than TCR binding, providing a possible explanation for the inability of TSST-1 to competitively block SEB binding to all DR1 molecules on cells (even though the binding sites of TSST-1 and SEB on DR1 overlap almost completely) and suggesting the possibility that T cell activation by superantigen could be directed by peptide antigen.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kim, J -- Urban, R G -- Strominger, J L -- Wiley, D C -- New York, N.Y. -- Science. 1994 Dec 16;266(5192):1870-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Children's Hospital, Boston, MA 02115.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7997880" target="_blank"〉PubMed〈/a〉
    Keywords: *Bacterial Toxins ; Binding Sites ; Crystallography, X-Ray ; Enterotoxins/*chemistry/metabolism ; HLA-DR1 Antigen/*chemistry/metabolism ; Humans ; Hydrogen Bonding ; Models, Molecular ; Protein Conformation ; Protein Structure, Secondary ; Receptors, Antigen, T-Cell/metabolism ; *Staphylococcus aureus ; Superantigens/*chemistry/metabolism
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  • 53
    Publication Date: 1994-07-15
    Description: Mutations in the p53 tumor suppressor are the most frequently observed genetic alterations in human cancer. The majority of the mutations occur in the core domain which contains the sequence-specific DNA binding activity of the p53 protein (residues 102-292), and they result in loss of DNA binding. The crystal structure of a complex containing the core domain of human p53 and a DNA binding site has been determined at 2.2 angstroms resolution and refined to a crystallographic R factor of 20.5 percent. The core domain structure consists of a beta sandwich that serves as a scaffold for two large loops and a loop-sheet-helix motif. The two loops, which are held together in part by a tetrahedrally coordinated zinc atom, and the loop-sheet-helix motif form the DNA binding surface of p53. Residues from the loop-sheet-helix motif interact in the major groove of the DNA, while an arginine from one of the two large loops interacts in the minor groove. The loops and the loop-sheet-helix motif consist of the conserved regions of the core domain and contain the majority of the p53 mutations identified in tumors. The structure supports the hypothesis that DNA binding is critical for the biological activity of p53, and provides a framework for understanding how mutations inactivate it.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cho, Y -- Gorina, S -- Jeffrey, P D -- Pavletich, N P -- NCI CA08748-29/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1994 Jul 15;265(5170):346-55.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cellular Biochemistry and Biophysics Program, 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/8023157" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Base Sequence ; Binding Sites ; Computer Graphics ; Crystallization ; Crystallography, X-Ray ; DNA/*chemistry/metabolism ; Genes, p53 ; Hydrogen Bonding ; Models, Molecular ; Molecular Sequence Data ; *Mutation ; Nucleic Acid Conformation ; *Protein Conformation ; Protein Structure, Secondary ; Tumor Suppressor Protein p53/*chemistry/genetics/metabolism
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  • 54
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    American Association for the Advancement of Science (AAAS)
    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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  • 55
    Publication Date: 1994-09-02
    Description: A family of uniform periodic polypeptides has been prepared by bacterial expression of the corresponding artificial genes, with the objective of exploring the potential for control of supramolecular organization in genetically engineered protein-based polymeric materials. The repeating units of the polypeptides consist of oligomeric alanyl-glycine sequences interspersed with glutamic acid residues inserted at intervals of 8 to 14 amino acids. Crystallization of such materials from formic acid produces beta-sheet structures in the solid state, as shown by vibrational spectroscopy, nuclear magnetic resonance spectroscopy, and wide-angle x-ray diffraction. The diffraction results, together with observations from electron microscopy, are consistent with the formation of needle-shaped lamellar crystals whose thickness is controlled by the periodicity of the primary sequence. These results can be used to control solid-state structure in macromolecular materials.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Krejchi, M T -- Atkins, E D -- Waddon, A J -- Fournier, M J -- Mason, T L -- Tirrell, D A -- New York, N.Y. -- Science. 1994 Sep 2;265(5177):1427-32.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Polymer Science and Engineering, University of Massachusetts, Amherst 01003.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8073284" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Base Sequence ; Computer Simulation ; Crystallization ; Crystallography, X-Ray ; Hydrogen Bonding ; Magnetic Resonance Spectroscopy ; Microscopy, Electron ; Models, Molecular ; Molecular Sequence Data ; Peptides/*chemistry ; *Protein Engineering ; *Protein Structure, Secondary ; Recombinant Proteins/*chemistry/ultrastructure ; Spectrum Analysis, Raman
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  • 56
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-01-28
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cohen, C -- Parry, D A -- AR17346/AR/NIAMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Jan 28;263(5146):488-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02254-9110.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8290957" target="_blank"〉PubMed〈/a〉
    Keywords: Crystallography, X-Ray ; *DNA-Binding Proteins ; Fungal Proteins/chemistry ; Hemagglutinin Glycoproteins, Influenza Virus ; Hemagglutinins, Viral/chemistry ; Leucine Zippers ; Models, Molecular ; Protein Kinases/chemistry ; *Protein Structure, Secondary ; *Protein Structure, Tertiary ; *Saccharomyces cerevisiae Proteins ; Spectrin/chemistry
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  • 57
    Publication Date: 1994-01-21
    Description: Mechanistic information and structure-based design methods have been used to design a series of nonpeptide cyclic ureas that are potent inhibitors of human immunodeficiency virus (HIV) protease and HIV replication. A fundamental feature of these inhibitors is the cyclic urea carbonyl oxygen that mimics the hydrogen-bonding features of a key structural water molecule. The success of the design in both displacing and mimicking the structural water molecule was confirmed by x-ray crystallographic studies. Highly selective, preorganized inhibitors with relatively low molecular weight and high oral bioavailability were synthesized.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lam, P Y -- Jadhav, P K -- Eyermann, C J -- Hodge, C N -- Ru, Y -- Bacheler, L T -- Meek, J L -- Otto, M J -- Rayner, M M -- Wong, Y N -- New York, N.Y. -- Science. 1994 Jan 21;263(5145):380-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Virology Research, DuPont Merck Pharmaceutical Company, Wilmington, DE 19880.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8278812" target="_blank"〉PubMed〈/a〉
    Keywords: Administration, Oral ; Animals ; Azepines/*chemistry/metabolism/pharmacokinetics/pharmacology ; Binding Sites ; Biological Availability ; Cell Line ; Crystallography, X-Ray ; Dogs ; *Drug Design ; Drug Evaluation, Preclinical ; HIV Protease/chemistry/metabolism ; HIV Protease Inhibitors/*chemistry/metabolism/pharmacokinetics/pharmacology ; HIV-1/drug effects/physiology ; Hydrogen Bonding ; Models, Molecular ; Molecular Conformation ; Molecular Weight ; Rats ; Recombinant Proteins/chemistry/metabolism ; Urea ; Virus Replication/drug effects
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  • 58
    Publication Date: 1994-10-07
    Description: Bacteriorhodopsin was selectively spin labeled at residues 72, 101, or 105 after replacement of the native amino acids by cysteine. Only the electron paramagnetic resonance spectrum of the label at 101 was time-dependent during the photocycle. The spectral change rose with the decay of the M intermediate and fell with recovery of the ground state. The transient signal is interpreted as the result of movement in the C-D or E-F interhelical loop, or in both, coincident with protonation changes at the key aspartate 96 residue. These results link the optically characterized intermediates with localized conformational changes in bacteriorhodopsin during the photocycle.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Steinhoff, H J -- Mollaaghababa, R -- Altenbach, C -- Hideg, K -- Krebs, M -- Khorana, H G -- Hubbell, W L -- EY05216/EY/NEI NIH HHS/ -- GM28289/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Oct 7;266(5182):105-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institut fur Biophysik, Ruhr-Universitat Bochum, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7939627" target="_blank"〉PubMed〈/a〉
    Keywords: Bacteriorhodopsins/*chemistry/genetics ; Electron Spin Resonance Spectroscopy ; Light ; Models, Molecular ; Mutagenesis, Site-Directed ; *Protein Conformation ; Protein Structure, Secondary ; Spin Labels
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  • 59
    Publication Date: 1994-12-23
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Steitz, T A -- Smerdon, S J -- Jager, J -- Joyce, C M -- GM28550/GM/NIGMS NIH HHS/ -- GM39546/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Dec 23;266(5193):2022-5.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7528445" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Binding Sites ; Crystallization ; Crystallography, X-Ray ; DNA Polymerase I/*chemistry/metabolism ; DNA-Directed RNA Polymerases/*chemistry/metabolism ; HIV Reverse Transcriptase ; Models, Molecular ; Molecular Sequence Data ; Protein Conformation ; Protein Folding ; RNA-Directed DNA Polymerase/*chemistry/metabolism ; Viral Proteins
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  • 60
    Publication Date: 1994-09-02
    Description: Mechanisms of guanosine triphosphate (GTP) hydrolysis by members of the G protein alpha subunit-p21ras superfamily of guanosine triphosphatases have been studied extensively but have not been well understood. High-resolution x-ray structures of the GTP gamma S and GDP.AlF4- complexes formed by the G protein Gi alpha 1 demonstrate specific roles in transition-state stabilization for two highly conserved residues. Glutamine204 (Gln61 in p21ras) stabilizes and orients the hydrolytic water in the trigonal-bipyramidal transition state. Arginine 178 stabilizes the negative charge at the equatorial oxygen atoms of the pentacoordinate phosphate intermediate. Conserved only in the G alpha family, this residue may account for the higher hydrolytic rate of G alpha proteins relative to those of the p21ras family members. The fold of Gi alpha 1 differs from that of the homologous Gt alpha subunit in the conformation of a helix-loop sequence located in the alpha-helical domain that is characteristic of these proteins; this site may participate in effector binding. The amino-terminal 33 residues are disordered in GTP gamma S-Gi alpha 1, suggesting a mechanism that may promote release of the beta gamma subunit complex when the alpha subunit is activated by GTP.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Coleman, D E -- Berghuis, A M -- Lee, E -- Linder, M E -- Gilman, A G -- Sprang, S R -- DK 46371/DK/NIDDK NIH HHS/ -- GM34497/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Sep 2;265(5177):1405-12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Dallas, TX.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8073283" target="_blank"〉PubMed〈/a〉
    Keywords: Aluminum Compounds/metabolism ; Arginine/chemistry ; Binding Sites ; Catalysis ; Computer Graphics ; Crystallography, X-Ray ; Fluorides/metabolism ; GTP-Binding Proteins/*chemistry/metabolism ; Glutamine/chemistry ; Guanosine 5'-O-(3-Thiotriphosphate)/metabolism ; Guanosine Diphosphate/metabolism ; Guanosine Triphosphate/*metabolism ; Helix-Loop-Helix Motifs ; Hydrogen Bonding ; Hydrolysis ; Models, Molecular ; *Protein Conformation ; Protein Structure, Secondary
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  • 61
    Publication Date: 1994-10-07
    Description: The structure of a protein triple helix has been determined at 1.9 angstrom resolution by x-ray crystallographic studies of a collagen-like peptide containing a single substitution of the consensus sequence. This peptide adopts a triple-helical structure that confirms the basic features determined from fiber diffraction studies on collagen: supercoiling of polyproline II helices and interchain hydrogen bonding that follows the model II of Rich and Crick. In addition, the structure provides new information concerning the nature of this protein fold. Each triple helix is surrounded by a cylinder of hydration, with an extensive hydrogen bonding network between water molecules and peptide acceptor groups. Hydroxyproline residues have a critical role in this water network. The interaxial spacing of triple helices in the crystal is similar to that in collagen fibrils, and the water networks linking adjacent triple helices in the crystal structure are likely to be present in connective tissues. The breaking of the repeating (X-Y-Gly)n pattern by a Gly--〉Ala substitution results in a subtle alteration of the conformation, with a local untwisting of the triple helix. At the substitution site, direct interchain hydrogen bonds are replaced with interstitial water bridges between the peptide groups. Similar conformational changes may occur in Gly--〉X mutated collagens responsible for the diseases osteogenesis imperfecta, chondrodysplasias, and Ehlers-Danlos syndrome IV.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bella, J -- Eaton, M -- Brodsky, B -- Berman, H M -- AR 19626/AR/NIAMS NIH HHS/ -- GM 21589/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Oct 7;266(5182):75-81.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Rutgers University, New Brunswick, NJ 08855.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7695699" target="_blank"〉PubMed〈/a〉
    Keywords: Alanine/chemistry ; Amino Acid Sequence ; Collagen/*chemistry ; Computer Graphics ; Crystallography, X-Ray ; Glycine/chemistry ; Hydrogen Bonding ; Hydroxyproline/chemistry ; Models, Molecular ; Molecular Sequence Data ; Molecular Structure ; Peptides/*chemistry ; *Protein Conformation ; Protein Structure, Secondary
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  • 62
    Publication Date: 1994-10-07
    Description: Para-hydroxybenzoate hydroxylase inserts oxygen into substrates by means of the labile intermediate, flavin C(4a)-hydroperoxide. This reaction requires transient isolation of the flavin and substrate from the bulk solvent. Previous crystal structures have revealed the position of the substrate para-hydroxybenzoate during oxygenation but not how it enters the active site. In this study, enzyme structures with the flavin ring displaced relative to the protein were determined, and it was established that these or similar flavin conformations also occur in solution. Movement of the flavin appears to be essential for the translocation of substrates and products into the solvent-shielded active site during catalysis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gatti, D L -- Palfey, B A -- Lah, M S -- Entsch, B -- Massey, V -- Ballou, D P -- Ludwig, M L -- GM 11106/GM/NIGMS NIH HHS/ -- GM 16429/GM/NIGMS NIH HHS/ -- GM 20877/GM/NIGMS NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1994 Oct 7;266(5182):110-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Chemistry, University of Michigan, Ann Arbor 48109.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7939628" target="_blank"〉PubMed〈/a〉
    Keywords: Benzoate 4-Monooxygenase ; Binding Sites ; Catalysis ; Computer Graphics ; Flavin-Adenine Dinucleotide/chemistry/metabolism ; Flavins/*chemistry/metabolism ; Hydrogen Bonding ; Mixed Function Oxygenases/*chemistry/metabolism ; Models, Molecular ; Molecular Conformation ; Oxidation-Reduction ; Parabens/metabolism ; Protein Conformation
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  • 63
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-05-13
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cowan, S W -- Rosenbusch, J P -- New York, N.Y. -- Science. 1994 May 13;264(5161):914-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Biozentrum, University of Basel, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8178151" target="_blank"〉PubMed〈/a〉
    Keywords: Algorithms ; Amino Acid Sequence ; Bacteriorhodopsins/chemistry ; Cell Membrane/chemistry ; Hydrogen Bonding ; Membrane Proteins/*chemistry ; Models, Molecular ; Molecular Sequence Data ; Porins/chemistry ; *Protein Folding ; Protein Structure, Secondary
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  • 64
    Publication Date: 1994-03-11
    Description: Crystal structures of seryl-tRNA synthetase from Thermus thermophilus complexed with two different analogs of seryl adenylate have been determined at 2.5 A resolution. The first complex is between the enzyme and seryl-hydroxamate-AMP (adenosine monophosphate), produced enzymatically in the crystal from adenosine triphosphate (ATP) and serine hydroxamate, and the second is with a synthetic analog of seryl adenylate (5'-O-[N-(L-seryl)-sulfamoyl]adenosine), which is a strong inhibitor of the enzyme. Both molecules are bound in a similar fashion by a network of hydrogen bond interactions in a deep hydrophilic cleft formed by the antiparallel beta sheet and surrounding loops of the synthetase catalytic domain. Four regions in the primary sequence are involved in the interactions, including the motif 2 and 3 regions of class 2 synthetases. Apart from the specific recognition of the serine side chain, the interactions are likely to be similar in all class 2 synthetases.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Belrhali, H -- Yaremchuk, A -- Tukalo, M -- Larsen, K -- Berthet-Colominas, C -- Leberman, R -- Beijer, B -- Sproat, B -- Als-Nielsen, J -- Grubel, G -- New York, N.Y. -- Science. 1994 Mar 11;263(5152):1432-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉EMBL Grenoble Outstation, France.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8128224" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine/*analogs & derivatives/chemical synthesis/metabolism ; Adenosine Monophosphate/*analogs & derivatives/chemical synthesis/metabolism ; Amino Acid Sequence ; Binding Sites ; Computer Graphics ; Crystallography, X-Ray ; Hydrogen Bonding ; Models, Molecular ; Molecular Sequence Data ; Protein Conformation ; Protein Structure, Secondary ; Sequence Alignment ; Serine/*analogs & derivatives/chemical synthesis/metabolism ; Serine-tRNA Ligase/*chemistry/metabolism ; Thermus thermophilus/*enzymology
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  • 65
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    American Association for the Advancement of Science (AAAS)
    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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  • 66
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    American Association for the Advancement of Science (AAAS)
    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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  • 67
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    American Association for the Advancement of Science (AAAS)
    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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  • 68
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-07-29
    Description: The helical path of the DNA in filamentous bacteriophage Pf1 was deduced from different kinds of existing structural information, including results from x-ray fiber diffraction. The DNA has the same pitch, 16 angstroms, as the surrounding helix of protein subunits; the rise and rotation per nucleotides are 6.1 angstroms and 132 degrees, respectively; and the phosphates are 2.5 angstroms from the axis. The DNA in Pf1 is, therefore, the most extended and twisted DNA structure known. On the basis of the DNA structure and extensive additional information about the protein, a model of the virion is proposed. In the model, the DNA bases reach out, into the protein, and the lysine and arginine side chains reach in, between the DNA bases, to stabilize the paraxial phosphate charges; the conformation of the protein subunit is a combination of alpha and 3(10) helices.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Liu, D J -- Day, L A -- GM42286/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Jul 29;265(5172):671-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Public Health Research Institute, New York, NY 10016.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8036516" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Capsid/*chemistry ; *Capsid Proteins ; DNA, Viral/*chemistry ; Inovirus/chemistry/genetics/*ultrastructure ; Models, Molecular ; Molecular Sequence Data ; Nucleic Acid Conformation ; Phosphates/analysis ; Protein Structure, Secondary ; X-Ray Diffraction
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  • 69
    Publication Date: 1994-03-11
    Description: The crystal structure of Thermus thermophilus seryl-transfer RNA synthetase, a class 2 aminoacyl-tRNA synthetase, complexed with a single tRNA(Ser) molecule was solved at 2.9 A resolution. The structure revealed how insertion of conserved base G20b from the D loop into the core of the tRNA determines the orientation of the long variable arm, which is a characteristic feature of most serine specific tRNAs. On tRNA binding, the antiparallel coiled-coil domain of one subunit of the synthetase makes contacts with the variable arm and T psi C loop of the tRNA and directs the acceptor stem of the tRNA into the active site of the other subunit. Specificity depends principally on recognition of the shape of tRNA(Ser) through backbone contacts and secondarily on sequence specific interactions.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Biou, V -- Yaremchuk, A -- Tukalo, M -- Cusack, S -- New York, N.Y. -- Science. 1994 Mar 11;263(5152):1404-10.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉European Molecular Biology Laboratory, Grenoble Outstation, France.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8128220" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphate/metabolism ; Amino Acid Sequence ; Base Composition ; Base Sequence ; Binding Sites ; Crystallography, X-Ray ; Models, Molecular ; Molecular Sequence Data ; Nucleic Acid Conformation ; Protein Conformation ; Protein Structure, Secondary ; RNA, Transfer, Amino Acyl/*chemistry/metabolism ; Serine-tRNA Ligase/*chemistry/metabolism ; Substrate Specificity ; Thermus thermophilus/*enzymology
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  • 70
    Publication Date: 1994-03-25
    Description: The three-dimensional structure of a member of the beta subfamily of chemokines, human macrophage inflammatory protein-1 beta (hMIP-1 beta), has been determined with the use of solution multidimensional heteronuclear magnetic resonance spectroscopy. Human MIP-1 beta is a symmetric homodimer with a relative molecular mass of approximately 16 kilodaltons. The structure of the hMIP-1 beta monomer is similar to that of the related alpha chemokine interleukin-8 (IL-8). However, the quaternary structures of the two proteins are entirely distinct, and the dimer interface is formed by a completely different set of residues. Whereas the IL-8 dimer is globular, the hMIP-1 beta dimer is elongated and cylindrical. This provides a rational explanation for the absence of cross-binding and reactivity between the alpha and beta chemokine subfamilies. Calculation of the solvation free energies of dimerization suggests that the formation and stabilization of the two different types of dimers arise from the burial of hydrophobic residues.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lodi, P J -- Garrett, D S -- Kuszewski, J -- Tsang, M L -- Weatherbee, J A -- Leonard, W J -- Gronenborn, A M -- Clore, G M -- New York, N.Y. -- Science. 1994 Mar 25;263(5154):1762-7.〈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, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8134838" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Chemokine CCL4 ; Computer Graphics ; Cytokines/*chemistry ; Humans ; Hydrogen Bonding ; Hydrogen-Ion Concentration ; Interleukin-8/chemistry ; Macrophage Inflammatory Proteins ; Magnetic Resonance Spectroscopy ; Models, Molecular ; Molecular Sequence Data ; Molecular Weight ; Monokines/*chemistry ; Protein Conformation ; Protein Structure, Secondary ; Sequence Alignment
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  • 71
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    American Association for the Advancement of Science (AAAS)
    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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  • 72
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-01-28
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gronenborn, A M -- Clore, G M -- New York, N.Y. -- Science. 1994 Jan 28;263(5146):536.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8290964" target="_blank"〉PubMed〈/a〉
    Keywords: Hydrogen Bonding ; Interleukin-1/*chemistry ; Models, Molecular ; *Protein Conformation ; Protein Folding ; Protein Structure, Secondary
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  • 73
    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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  • 74
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-08-26
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉O'Brien, C -- New York, N.Y. -- Science. 1994 Aug 26;265(5176):1176-7.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8066459" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Diphosphate/metabolism ; Adenosine Triphosphate/biosynthesis ; Crystallization ; Crystallography, X-Ray ; Intracellular Membranes/enzymology ; Mitochondria/enzymology ; Models, Molecular ; Protein Conformation ; Proton-Translocating ATPases/*chemistry/metabolism ; Protons
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  • 75
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-03-11
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Marx, J -- New York, N.Y. -- Science. 1994 Mar 11;263(5152):1373.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8128216" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Computer Graphics ; Crystallography, X-Ray ; Humans ; Models, Molecular ; Phosphates/metabolism ; Protein Conformation ; Protein Folding ; Protein Tyrosine Phosphatases/*chemistry/metabolism ; Tungsten Compounds/metabolism
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  • 76
    Publication Date: 1994-11-18
    Description: Solution structures of two Src homology 3 (SH3) domain-ligand complexes have been determined by nuclear magnetic resonance. Each complex consists of the SH3 domain and a nine-residue proline-rich peptide selected from a large library of ligands prepared by combinatorial synthesis. The bound ligands adopt a left-handed polyproline type II (PPII) helix, although the amino to carboxyl directionalities of their helices are opposite. The peptide orientation is determined by a salt bridge formed by the terminal arginine residues of the ligands and the conserved aspartate-99 of the SH3 domain. Residues at positions 3, 4, 6, and 7 of both peptides also intercalate into the ligand-binding site; however, the respective proline and nonproline residues show exchanged binding positions in the two complexes. These structural results led to a model for the interactions of SH3 domains with proline-rich peptides that can be used to predict critical residues in complexes of unknown structure. The model was used to identify correctly both the binding orientation and the contact and noncontact residues of a peptide derived from the nucleotide exchange factor Sos in association with the amino-terminal SH3 domain of the adaptor protein Grb2.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Feng, S -- Chen, J K -- Yu, H -- Simon, J A -- Schreiber, S L -- GM44993/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Nov 18;266(5188):1241-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Department of Chemistry, Harvard University, Cambridge, MA 02138.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7526465" target="_blank"〉PubMed〈/a〉
    Keywords: *Adaptor Proteins, Signal Transducing ; Alanine/chemistry ; Amino Acid Sequence ; Arginine/chemistry ; Binding Sites ; GRB2 Adaptor Protein ; Glycine/chemistry ; Guanine Nucleotide Exchange Factors ; Ligands ; Magnetic Resonance Spectroscopy ; Models, Molecular ; Molecular Sequence Data ; Oligopeptides/chemistry/*metabolism ; Peptides/chemistry/metabolism ; Proline/chemistry ; Proline-Rich Protein Domains ; Protein Conformation ; Protein Structure, Secondary ; Protein-Tyrosine Kinases/chemistry/*metabolism ; Proteins/chemistry/metabolism ; Proto-Oncogene Proteins pp60(c-src)/chemistry/*metabolism ; src-Family Kinases
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  • 77
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    American Association for the Advancement of Science (AAAS)
    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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  • 78
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-01-14
    Description: The structure of the DNA binding domain, determined at 1.8 angstrom resolution, contains a three-helix bundle that is capped by a four-stranded antiparallel beta sheet. This structure is a variant of the helix-turn-helix motif, typified by catabolite activator protein. In the heat shock transcription factor, the first helix of the motif (alpha 2) has an alpha-helical bulge and a proline-induced kink. The angle between the two helices of the motif (alpha 2 and alpha 3) is about 20 degrees smaller than the average for canonical helix-turn-helix proteins. Nevertheless, the relative positions of the first and third helices of the bundle (alpha 1 and alpha 3) are conserved. It is proposed here that the first helix of the three-helix bundle be considered a component of the helix-turn-helix motif.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Harrison, C J -- Bohm, A A -- Nelson, H C -- GM08295/GM/NIGMS NIH HHS/ -- GM44086/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Jan 14;263(5144):224-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉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/8284672" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Crystallography, X-Ray ; DNA/*metabolism ; DNA-Binding Proteins/*chemistry/metabolism ; *Heat-Shock Proteins ; *Helix-Loop-Helix Motifs ; Models, Molecular ; Molecular Sequence Data ; Protein Structure, Secondary ; Transcription Factors/*chemistry
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  • 79
    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
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  • 80
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    American Association for the Advancement of Science (AAAS)
    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
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  • 81
    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
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  • 82
    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
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  • 83
    Publication Date: 1993-08-06
    Description: The structure of the bifunctional, pyridoxal phosphate-dependent enzyme dialkylglycine decarboxylase was determined to 2.1-angstrom resolution. Model building suggests that a single cleavage site catalyzes both decarboxylation and transamination by maximizing stereoelectronic advantages and providing electrostatic and general base catalysis. The enzyme contains two binding sites for alkali metal ions. One is located near the active site and accounts for the dependence of activity on potassium ions. The other is located at the carboxyl terminus of an alpha helix. These sites help show how proteins can specifically bind alkali metals and how these ions can exert functional effects.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Toney, M D -- Hohenester, E -- Cowan, S W -- Jansonius, J N -- GM13854/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1993 Aug 6;261(5122):756-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Structural Biology, University of Basel, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8342040" target="_blank"〉PubMed〈/a〉
    Keywords: Amination ; Amino Acid Sequence ; Binding Sites ; Carboxy-Lyases/*chemistry/metabolism ; Catalysis ; Computer Graphics ; Decarboxylation ; Metals, Alkali/*metabolism ; Models, Molecular ; Molecular Sequence Data ; Protein Conformation ; Protein Structure, Secondary ; X-Ray Diffraction
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  • 84
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    American Association for the Advancement of Science (AAAS)
    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
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  • 85
    Publication Date: 1993-11-12
    Description: Rapid photoinduced electron transfer is demonstrated over a distance of greater than 40 angstroms between metallointercalators that are tethered to the 5' termini of a 15-base pair DNA duplex. An oligomeric assembly was synthesized in which the donor is Ru(phen)2dppz2+ (phen, phenanthroline, and dppz, dipyridophenazine) and the acceptor is Rh(phi)2phen3+ (phi, phenanthrenequinone diimine). These metal complexes are intercalated either one or two base steps in from the helix termini. Although the ruthenium-modified oligonucleotide hybridized to an unmodified complement luminesces intensely, the ruthenium-modified oligomer hybridized to the rhodium-modified oligomer shows no detectable luminescence. Time-resolved studies point to a lower limit of 10(9) per second for the quenching rate. No quenching was observed upon metallation of two complementary octamers by Ru(phen)3(2+) and Rh(phen)3(3+) under conditions where the phen complexes do not intercalate. The stacked aromatic heterocycles of the DNA duplex therefore serve as an efficient medium for coupling electron donors and acceptors over very long distances.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Murphy, C J -- Arkin, M R -- Jenkins, Y -- Ghatlia, N D -- Bossmann, S H -- Turro, N J -- Barton, J K -- GM49216/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1993 Nov 12;262(5136):1025-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Beckman Institute, California Institute of Technology, Pasadena 91125.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7802858" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; DNA/*chemistry ; *Electrons ; Intercalating Agents/*chemistry ; Lasers ; Luminescence ; Models, Molecular ; Molecular Sequence Data ; Nucleic Acid Conformation ; Oligodeoxyribonucleotides/*chemistry ; Organometallic Compounds/chemistry ; Phenanthrenes/chemistry ; Phenanthrolines/chemistry ; Photochemistry
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  • 86
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    American Association for the Advancement of Science (AAAS)
    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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  • 87
    Publication Date: 1993-02-12
    Description: Biomolecular membranes display rich statistical mechanical behavior. They are classified as liquid in the absence of shear elasticity in the plane of the membrane and tethered (solid) when the neighboring molecules or subunits are connected and the membranes exhibit solid-like elastic behavior in the plane of the membrane. The spectrin skeleton of red blood cells was studied as a model tethered membrane. The static structure factor of the skeletons, measured by small-angle x-ray and light scattering, was fitted with a structure factor predicted with a model calculation. The model describes tethered membrane sheets with free edges in a flat phase, which is a locally rough but globally flat membrane configuration. The fit was good for large scattering vectors. The membrane roughness exponent, zeta, defined through h alpha L zeta, where h is the average amplitude of out-of-plane fluctuations and L is the linear membrane dimension, was determined to be 0.65 +/- 0.10. Computer simulations of model red blood cell skeletons also showed this flat phase. The value for the roughness exponent, which was determined from the scaling properties of membranes of different sizes, was consistent with that from the experiments.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schmidt, C F -- Svoboda, K -- Lei, N -- Petsche, I B -- Berman, L E -- Safinya, C R -- Grest, G S -- New York, N.Y. -- Science. 1993 Feb 12;259(5097):952-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cellular and Developmental Biology, Harvard University, Cambridge, MA 02138.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8438153" target="_blank"〉PubMed〈/a〉
    Keywords: Chemistry, Physical ; Computer Simulation ; Electrochemistry ; Erythrocyte Membrane/chemistry/*ultrastructure ; Light ; Mathematics ; Models, Molecular ; Physicochemical Phenomena ; Scattering, Radiation ; Spectrin/chemistry/*ultrastructure ; X-Rays
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  • 88
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1993-04-16
    Description: Klenow fragment of Escherichia coli DNA polymerase I, which was cocrystallized with duplex DNA, positioned 11 base pairs of DNA in a groove that lies at right angles to the cleft that contains the polymerase active site and is adjacent to the 3' to 5' exonuclease domain. When the fragment bound DNA, a region previously referred to as the "disordered domain" became more ordered and moved along with two helices toward the 3' to 5' exonuclease domain to form the binding groove. A single-stranded, 3' extension of three nucleotides bound to the 3' to 5' exonuclease active site. Although this cocrystal structure appears to be an editing complex, it suggests that the primer strand approaches the catalytic site of the polymerase from the direction of the 3' to 5' exonuclease domain and that the duplex DNA product may bend to enter the cleft that contains the polymerase catalytic site.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Beese, L S -- Derbyshire, V -- Steitz, T A -- GM28550/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1993 Apr 16;260(5106):352-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8469987" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Binding Sites ; Crystallization ; DNA/chemistry/*metabolism ; DNA Polymerase I/*chemistry/metabolism ; DNA Replication ; DNA, Single-Stranded/chemistry/metabolism ; Escherichia coli/*enzymology ; Models, Molecular ; Molecular Sequence Data ; Protein Conformation ; Templates, Genetic
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  • 89
    Publication Date: 1993-01-29
    Description: The phosphocarrier protein IIIGlc is an integral component of the bacterial phosphotransferase (PTS) system. Unphosphorylated IIIGlc inhibits non-PTS carbohydrate transport systems by binding to diverse target proteins. The crystal structure at 2.6 A resolution of one of the targets, glycerol kinase (GK), in complex with unphosphorylated IIIGlc, glycerol, and adenosine diphosphate was determined. GK contains a region that is topologically identical to the adenosine triphosphate binding domains of hexokinase, the 70-kD heat shock cognate, and actin. IIIGlc binds far from the catalytic site of GK, indicating that long-range conformational changes mediate the inhibition of GK by IIIGlc. GK and IIIGlc are bound by hydrophobic and electrostatic interactions, with only one hydrogen bond involving an uncharged group. The phosphorylation site of IIIGlc, His90, is buried in a hydrophobic environment formed by the active site region of IIIGlc and a 3(10) helix of GK, suggesting that phosphorylation prevents IIIGlc binding to GK by directly disrupting protein-protein interactions.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hurley, J H -- Faber, H R -- Worthylake, D -- Meadow, N D -- Roseman, S -- Pettigrew, D W -- Remington, S J -- 5-R37 GM38759/GM/NIGMS NIH HHS/ -- GM 42618-01A1/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1993 Jan 29;259(5095):673-7.〈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/8430315" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Diphosphate/metabolism ; Amino Acid Sequence ; Binding Sites ; Escherichia coli/*enzymology ; Escherichia coli Proteins ; Glycerol Kinase/*chemistry/*metabolism ; Hydrogen Bonding ; Models, Molecular ; Models, Structural ; Phosphoenolpyruvate Sugar Phosphotransferase System/*chemistry/*metabolism ; *Protein Structure, Secondary
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  • 90
    Publication Date: 1993-12-24
    Description: The elongated proteins of the spectrin family (dystrophin, alpha-actinin, and spectrin) contain tandemly repeated segments and form resilient cellular meshworks by cross-linking actin filaments. The structure of one of the repetitive segments of alpha-spectrin was determined at a 1.8 angstrom resolution. A segment consists of a three-helix bundle. A model of the interface between two tandem segments suggests that hydrophobic interactions between segments may constrain intersegment flexibility. The helix side chain interactions explain how mutations that are known to produce hemolytic anemias disrupt spectrin associations that sustain the integrity of the erythrocyte membrane.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Yan, Y -- Winograd, E -- Viel, A -- Cronin, T -- Harrison, S C -- Branton, D -- CA 13202/CA/NCI NIH HHS/ -- HL 17411/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1993 Dec 24;262(5142):2027-30.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, Harvard University, Cambridge, MA 02138.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8266097" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Crystallization ; Drosophila ; Models, Molecular ; Molecular Sequence Data ; Protein Conformation ; Spectrin/*chemistry
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  • 91
    Publication Date: 1993-05-21
    Description: The three-dimensional solution structure of the DNA binding domain (DBD) of the retinoid X receptor alpha (RXR alpha) was determined by nuclear magnetic resonance spectroscopy. The two zinc fingers of the RXR DBD fold to form a single structural domain that consists of two perpendicularly oriented helices and that resembles the corresponding regions of the glucocorticoid and estrogen receptors (GR and ER, respectively). However, in contrast to the DBDs of the GR and ER, the RXR DBD contains an additional helix immediately after the second zinc finger. This third helix mediates both protein-protein and protein-DNA interactions required for cooperative, dimeric binding of the RXR DBD to DNA. Identification of the third helix in the RXR DBD thus defines a structural feature required for selective dimerization of the RXR on hormone response elements composed of half-sites (5'-AGGTCA-3') arranged as tandem repeats.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lee, M S -- Kliewer, S A -- Provencal, J -- Wright, P E -- Evans, R M -- New York, N.Y. -- Science. 1993 May 21;260(5111):1117-21.〈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/8388124" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Base Sequence ; DNA/*metabolism ; DNA-Binding Proteins/*chemistry/metabolism ; Magnetic Resonance Spectroscopy ; Models, Molecular ; Molecular Sequence Data ; Nuclear Proteins/*chemistry/metabolism ; Oligodeoxyribonucleotides ; Protein Conformation ; Protein Structure, Secondary ; Receptors, Cell Surface/*chemistry/metabolism ; *Receptors, Retinoic Acid ; Repetitive Sequences, Nucleic Acid ; Retinoid X Receptors ; *Transcription Factors ; Zinc Fingers
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 92
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1993-06-04
    Description: Pectate lyases are secreted by pathogens and initiate soft-rot diseases in plants by cleaving polygalacturonate, a major component of the plant cell wall. The three-dimensional structure of pectate lyase C from Erwinia chrysanthemi has been solved and refined to a resolution of 2.2 angstroms. The enzyme folds into a unique motif of parallel beta strands coiled into a large helix. Within the core, the amino acids form linear stacks and include a novel asparagine ladder. The sequence similarities that pectate lyases share with pectin lyases, pollen and style proteins, and tubulins suggest that the parallel beta helix motif may occur in a broad spectrum of proteins.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Yoder, M D -- Keen, N T -- Jurnak, F -- New York, N.Y. -- Science. 1993 Jun 4;260(5113):1503-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of California, Riverside 92521.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8502994" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Binding Sites ; Calcium ; Crystallography ; Isoenzymes/*chemistry ; Models, Molecular ; Molecular Sequence Data ; Pectobacterium chrysanthemi/enzymology ; Polysaccharide-Lyases/*chemistry ; Protein Structure, Secondary ; *Protein Structure, Tertiary
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  • 93
    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
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  • 94
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1993-07-02
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Taylor, E W -- New York, N.Y. -- Science. 1993 Jul 2;261(5117):35-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Genetics and Cell Biology, University of Chicago, IL 60637.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8316856" target="_blank"〉PubMed〈/a〉
    Keywords: Actins/chemistry/metabolism ; Actomyosin/chemistry ; Adenosine Triphosphate/metabolism ; Models, Biological ; Models, Molecular ; *Muscle Contraction ; Myosin Subfragments/*chemistry/metabolism ; *Protein Conformation ; Protein Structure, Secondary ; X-Ray Diffraction
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  • 95
    Publication Date: 1993-10-29
    Description: A 24-amino acid peptide designed to solubilize integral membrane proteins has been synthesized. The design was for an amphipathic alpha helix with a "flat" hydrophobic surface that would interact with a transmembrane protein as a detergent. When mixed with peptide, 85 percent of bacteriorhodopsin and 60 percent of rhodopsin remained in solution over a period of 2 days in their native forms. The crystal structure of peptide alone showed it to form an antiparallel four-helix bundle in which monomers interact, flat surface to flat surface, as predicted.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schafmeister, C E -- Miercke, L J -- Stroud, R M -- GM24485/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1993 Oct 29;262(5134):734-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Biophysics, University of California, San Francisco 94143-0448.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8235592" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Bacteriorhodopsins/chemistry ; Crystallography, X-Ray ; Detergents/chemical synthesis/*chemistry ; Drug Design ; Membrane Proteins/*chemistry ; Models, Molecular ; Molecular Sequence Data ; Peptides/chemical synthesis/*chemistry ; Protein Conformation ; Protein Structure, Secondary ; Rhodopsin/chemistry
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  • 96
    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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  • 97
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    Unknown
    American Association for the Advancement of Science (AAAS)
    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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  • 98
    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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  • 99
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1993-08-06
    Description: Metalloenzymes effect a variety of important chemical transformations, often involving small molecule substrates or products such as molecular oxygen, hydrogen, nitrogen, and water. A diverse array of ions or metal clusters is observed at the active-site cores, but living systems use basic recurring structures that have been modified or tuned for specific purposes. Inorganic chemists are actively involved in the elucidation of the structure, spectroscopy, and mechanism of action of these biological catalysts, in part through a synthetic modeling approach involving biomimetic studies.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Karlin, K D -- GM28962/GM/NIGMS NIH HHS/ -- GM45971/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1993 Aug 6;261(5122):701-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7688141" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Oxidoreductases/chemistry/metabolism ; Binding Sites ; Electron Transport ; Enzymes/*chemistry/metabolism ; Hydrolysis ; Iron-Sulfur Proteins/chemistry/metabolism ; Metalloproteins/*chemistry/metabolism ; *Models, Chemical ; Models, Molecular ; Nitric Oxide/metabolism ; Nitric Oxide Synthase ; Oxidation-Reduction ; Peptides/metabolism
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  • 100
    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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