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  • Structure-Activity Relationship  (204)
  • AERODYNAMICS
  • Cell & Developmental Biology
  • Chemistry
  • GEOPHYSICS
  • Inorganic Chemistry
  • American Association for the Advancement of Science (AAAS)  (276)
  • 1985-1989  (161)
  • 1980-1984  (115)
  • 1930-1934
  • 1915-1919
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  • 1
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1989-03-24
    Description: The N-methyl-D-aspartate (NMDA) class of excitatory amino acid receptors regulates the strength and stability of excitatory synapses and appears to play a major role in excitotoxic neuronal death associated with stroke and epilepsy. The conductance increase gated by NMDA is potentiated by the amino acid glycine, which acts at an allosteric site tightly coupled to the NMDA receptor. Indole-2-carboxylic acid (I2CA) specifically and competitively inhibits the potentiation by glycine of NMDA-gated current. In solutions containing low levels of glycine, I2CA completely blocks the response to NMDA, suggesting that NMDA alone is not sufficient for channel activation. I2CA will be useful for defining the interaction of glycine with NMDA receptors and for determining the in vivo role of glycine in excitotoxicity and synapse stabilization.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Huettner, J E -- HL-35034/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1989 Mar 24;243(4898):1611-3.〈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/2467381" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Aspartic Acid/*analogs & derivatives/physiology ; Cells, Cultured ; Electric Conductivity ; Glycine/*antagonists & inhibitors ; In Vitro Techniques ; Indoles/*pharmacology ; Ion Channels/drug effects ; N-Methylaspartate ; Neural Inhibition ; Rats ; Receptors, N-Methyl-D-Aspartate ; Receptors, Neurotransmitter/*drug effects ; Structure-Activity Relationship
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  • 2
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1989-03-24
    Description: Repeating copolymers of (dT-dC)n.(dA-dG)n sequences (TC.AGn) can assume a hinged DNA structure (H-DNA) which is composed of triple-stranded and single-stranded regions. A model for the formation of H-DNA is proposed, based on two-dimensional gel electrophoretic analysis of DNA's with different lengths of (TC.AG)n copolymers. In this model, H-DNA formation is initiated at a small denaturation bubble in the interior of the copolymer, which allows the duplexes on either side to rotate slightly and to fold back, in order to make the first base triplet. This nucleation establishes which of several nonequivalent H-DNA conformations is to be assumed by any DNA molecule, thereby trapping each molecule in one of several metastable conformers that are not freely interconvertible. Subsequently, the acceptor region spools up single-stranded polypyrimidines as they are released by progressive denaturation of the donor region; both the spooling and the denaturation result in relaxation of negative supercoils in the rest of the DNA molecule. From the model, it can be predicted that the levels of supercoiling of the DNA determine which half of the (dT-dC)n repeat is to become the donated third strand.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Htun, H -- Dahlberg, J E -- GM 30220/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1989 Mar 24;243(4898):1571-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiological Chemistry, University of Wisconsin-Madison 53706.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2648571" target="_blank"〉PubMed〈/a〉
    Keywords: DNA/*ultrastructure ; DNA, Single-Stranded ; DNA, Superhelical ; *Nucleic Acid Conformation ; Structure-Activity Relationship
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  • 3
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1989-03-03
    Description: Monoclonal antibodies have been induced that are capable of catalyzing specific hydrolysis of the Gly-Phe bond of peptide substrates at neutral pH with a metal complex cofactor. The antibodies were produced by immunizing with a Co(III) triethylenetetramine (trien)-peptide hapten. These antibodies as a group are capable of binding trien complexes of not only Co(III) but also of numerous other metals. Six peptides were examined as possible substrates with the antibodies and various metal complexes. Two of these peptides were cleaved by several of the antibodies. One antibody was studied in detail, and cleavage was observed for the substrates with the trien complexes of Zn(II), Ga(III), Fe(III), In(III), Cu(II), Ni(II), Lu(III), Mg(II), or Mn(II) as cofactors. A turnover number of 6 x 10(-4) per second was observed for these substrates. These results demonstrate the feasibility of the use of cofactor-assisted catalysis in an antibody binding site to accomplish difficult chemical transformations.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Iverson, B L -- Lerner, R A -- New York, N.Y. -- Science. 1989 Mar 3;243(4895):1184-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Research Institute of Scripps Clinic, La Jolla, CA 92037.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2922606" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; *Antibodies, Monoclonal ; Antigens/immunology ; Binding Sites, Antibody ; Catalysis ; Chemical Phenomena ; Chemistry ; Cobalt/immunology/metabolism ; Glycine/metabolism ; Haptens/immunology ; Hydrogen-Ion Concentration ; Hydrolysis ; Immunization ; Metals/metabolism ; Mice ; Molecular Sequence Data ; Molecular Structure ; Oligopeptides/*metabolism ; Phenylalanine/metabolism ; Trientine/immunology
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  • 4
    Publication Date: 1989-03-24
    Description: The compound 1,6-dihydropurine ribonucleoside, prepared by reduction of nebularine in the presence of ultraviolet light, is bound by adenosine deaminase approximately 10(8)-fold less tightly than 6-hydroxy-1,6-dihydropurine ribonucleoside, a nearly ideal transition-state analog. This difference in affinities, which is associated with the presence of a single hydroxyl group in the second compound, suggests the degree to which one or a few hydrogen bonds may stabilize the transition state in an enzyme reaction of this type.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kati, W M -- Wolfenden, R -- GM-18325/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1989 Mar 24;243(4898):1591-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of North Carolina, Chapel Hill 27514.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2928795" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Deaminase/*metabolism ; Adenosine Deaminase Inhibitors ; Hydrogen Bonding ; Hydroxides ; Ligands ; Nucleoside Deaminases/*metabolism ; Structure-Activity Relationship ; Substrate Specificity ; Thermodynamics
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  • 5
    Publication Date: 1989-04-07
    Description: Protein engineering and x-ray crystallography have been used to study the role of a surface loop that is present in pancreatic phospholipases but is absent in snake venom phospholipases. Removal of residues 62 to 66 from porcine pancreatic phospholipase A2 does not change the binding constant for micelles significantly, but it improves catalytic activity up to 16 times on micellar (zwitterionic) lecithin substrates. In contrast, the decrease in activity on negatively charged substrates is greater than fourfold. A crystallographic study of the mutant enzyme shows that the region of the deletion has a well-defined structure that differs from the structure of the wild-type enzyme. No structural changes in the active site of the enzyme were detected.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kuipers, O P -- Thunnissen, M M -- de Geus, P -- Dijkstra, B W -- Drenth, J -- Verheij, H M -- de Haas, G H -- New York, N.Y. -- Science. 1989 Apr 7;244(4900):82-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of Utrecht, The Netherlands.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2704992" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Crystallography ; Enzyme Activation ; Kinetics ; Molecular Sequence Data ; Mutation ; Pancreas/enzymology ; Phospholipases/*metabolism ; Phospholipases A/genetics/*metabolism/physiology ; Phospholipases A2 ; *Protein Conformation ; Snake Venoms/analysis ; Structure-Activity Relationship ; Swine
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  • 6
    Publication Date: 1989-09-22
    Description: Bleomycin is a metal- and oxygen-dependent DNA cleaver. The chemistry of DNA damage has been proposed to involve rate-limiting abstraction of the 4'-hydrogen. A DNA fragment has been prepared that contains [4'-2H]thymidine residues of high isotopic content. Primary kinetic isotope effects have been directly observed at individual thymidine residues with DNA sequencing technology.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kozarich, J W -- Worth, L Jr -- Frank, B L -- Christner, D F -- Vanderwall, D E -- Stubbe, J -- GM 34454/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1989 Sep 22;245(4924):1396-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2476851" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; *Bleomycin ; *DNA Damage ; Deuterium ; Iron ; Oxygen ; Structure-Activity Relationship ; Thymidine
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  • 7
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1989-08-04
    Description: The origin of allostery is an unanswered question in the evolution of complex regulatory proteins. Anabolic ornithine transcarbamoylase, a trimer of identical subunits, is not an allosteric enzyme per se. However, when the active-site residue arginine-106 of the Escherichia coli enzyme is replaced with a glycine through site-directed mutagenesis, the resultant mutant enzyme manifests substrate cooperativity that is absent in the wild-type enzyme. Both homotropic and heterotropic interactions occur in the mutant enzyme. The initial velocity saturation curves of the substrates, carbamoyl phosphate and L-ornithine, conform to the Hill equation. The observed cooperativity depends on substrate but not enzyme concentration. The finding underscores the possibility that a single mutation of the enzyme in the cell could turn transcarbamoylation into a regulatory junction in the biosynthesis of L-arginine and urea.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kuo, L C -- Zambidis, I -- Caron, C -- DK01721/DK/NIDDK NIH HHS/ -- DK38089/DK/NIDDK NIH HHS/ -- New York, N.Y. -- Science. 1989 Aug 4;245(4917):522-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Metcalf Center for Science and Engineering, Boston University, MA 02215.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2667139" target="_blank"〉PubMed〈/a〉
    Keywords: Allosteric Regulation ; Binding Sites ; Carbamyl Phosphate/metabolism ; Escherichia coli/*enzymology ; Glycine ; Kinetics ; Macromolecular Substances ; *Mutation ; Ornithine/metabolism ; Ornithine Carbamoyltransferase/*genetics/metabolism ; Structure-Activity Relationship ; Zinc/pharmacology
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  • 8
    Publication Date: 1989-08-18
    Description: CD4 is a cell surface glycoprotein that is thought to interact with nonpolymorphic determinants of class II major histocompatibility (MHC) molecules. CD4 is also the receptor for the human immunodeficiency virus (HIV), binding with high affinity to the HIV-1 envelope glycoprotein, gp120. Homolog-scanning mutagenesis was used to identify CD4 regions that are important in class II MHC binding and to determine whether the gp120 and class II MHC binding sites of CD4 are related. Class II MHC binding was abolished by mutations in each of the first three immunoglobulin-like domains of CD4. The gp120 binding could be abolished without affecting class II MHC binding and vice versa, although at least one mutation examined reduced both functions significantly. These findings indicate that, while there may be overlap between the gp120 and class II MHC binding sites of CD4, these sites are distinct and can be separated. Thus it should be possible to design CD4 analogs that can block HIV infectivity but intrinsically lack the ability to affect the normal immune response by binding to class II MHC molecules.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lamarre, D -- Ashkenazi, A -- Fleury, S -- Smith, D H -- Sekaly, R P -- Capon, D J -- New York, N.Y. -- Science. 1989 Aug 18;245(4919):743-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratoire d'Immunologie, Institut de Recherches Cliniques de Montreal, Quebec, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2549633" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Antigens, Surface ; Binding Sites ; DNA, Recombinant ; HIV/*metabolism ; HIV Envelope Protein gp120 ; HLA-DP Antigens/immunology ; Histocompatibility Antigens Class II/*immunology ; Humans ; Hybridomas ; Mice ; Molecular Sequence Data ; Mutation ; Receptors, HIV ; Receptors, Virus/genetics/immunology/*metabolism ; Retroviridae Proteins/immunology/*metabolism ; Rosette Formation ; Structure-Activity Relationship ; T-Lymphocytes/immunology/metabolism ; Transfection
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  • 9
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1989-03-31
    Description: C/EBP is a rat liver nuclear protein capable of sequence-specific interaction with DNA. The DNA sequences to which C/EBP binds in vitro have been implicated in the control of messenger RNA synthesis. It has therefore been predicted that C/EBP will play a role in regulating gene expression in mammalian cells. The region of the C/EBP polypeptide required for direct interaction with DNA has been identified and shown to bear amino acid sequence relatedness with the product of the myc, fos, and jun proto-oncogenes. The arrangement of these related amino acid sequences led to the prediction of a new structural motif, termed the "leucine zipper," that plays a role in facilitating sequence-specific interaction between protein and DNA. Experimental tests now provide support for the leucine zipper hypothesis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Landschulz, W H -- Johnson, P F -- McKnight, S L -- New York, N.Y. -- Science. 1989 Mar 31;243(4899):1681-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Carnegie Institution of Washington, Department of Embryology, Baltimore, MD 21210.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2494700" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Binding Sites ; CCAAT-Enhancer-Binding Proteins ; Cross-Linking Reagents ; DNA/*metabolism ; Glutaral ; Leucine ; Liver/*analysis ; Macromolecular Substances ; Molecular Weight ; Mutation ; Nuclear Proteins/genetics/*metabolism ; Protein Conformation ; Rats ; Repetitive Sequences, Nucleic Acid ; Structure-Activity Relationship
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  • 10
    Publication Date: 1989-11-17
    Description: The surface forces apparatus technique was used for measuring the adhesion, deformation, and fusion of bilayers supported on mica surfaces in aqueous solutions. The most important force leading to the direct fusion of bilayers is the hydrophobic interaction, although the occurrence of fusion is not simply related to the force law between bilayers. Bilayers do not need to "overcome" some repulsive force barrier, such as hydration, before they can fuse. Instead, once bilayer surfaces come within about 1 nanometer of each other, local deformations and molecular rearrangements allow them to "bypass" these forces.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Helm, C A -- Israelachvili, J N -- McGuiggan, P M -- New York, N.Y. -- Science. 1989 Nov 17;246(4932):919-22.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemical and Nuclear Engineering, University of California, Santa Barbara 93106.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2814514" target="_blank"〉PubMed〈/a〉
    Keywords: Chemical Phenomena ; Chemistry ; *Lipid Bilayers ; Models, Biological ; Models, Structural ; Phosphatidylcholines ; Phosphatidylethanolamines
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  • 11
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1989-07-28
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Waldrop, M M -- New York, N.Y. -- Science. 1989 Jul 28;245(4916):354-5.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2756423" target="_blank"〉PubMed〈/a〉
    Keywords: *Catalysis ; Chemical Phenomena ; Chemistry ; *Enzymes ; Technology, Pharmaceutical
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  • 12
    Publication Date: 1989-12-01
    Description: A single-site mutant of Escherichia coli glutaminyl-synthetase (D235N, GlnRS7) that incorrectly acylates in vivo the amber suppressor supF tyrosine transfer RNA (tRNA(Tyr] with glutamine has been described. Two additional mutant forms of the enzyme showing this misacylation property have now been isolated in vivo (D235G, GlnRS10; I129T, GlnRS15). All three mischarging mutant enzymes still retain a certain degree of tRNA specificity; in vivo they acylate supE glutaminyl tRNA (tRNA(Gln] and supF tRNA(Tyr) but not a number of other suppressor tRNA's. These genetic experiments define two positions in GlnRS where amino acid substitution results in a relaxed specificity of tRNA discrimination. The crystal structure of the GlnRS:tRNA(Gln) complex provides a structural basis for interpreting these data. In the wild-type enzyme Asp235 makes sequence-specific hydrogen bonds through its side chain carboxylate group with base pair G3.C70 in the minor groove of the acceptor stem of the tRNA. This observation implicates base pair 3.70 as one of the identity determinants of tRNA(Gln). Isoleucine 129 is positioned adjacent to the phosphate of nucleotide C74, which forms part of a hairpin structure adopted by the acceptor end of the complexed tRNA molecule. These results identify specific areas in the structure of the complex that are critical to accurate tRNA discrimination by GlnRS.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Perona, J J -- Swanson, R N -- Rould, M A -- Steitz, T A -- Soll, D -- New York, N.Y. -- Science. 1989 Dec 1;246(4934):1152-4.〈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/2686030" target="_blank"〉PubMed〈/a〉
    Keywords: Acylation ; Amino Acyl-tRNA Synthetases/genetics/*metabolism ; Aspartic Acid ; Binding Sites ; Crystallization ; Escherichia coli/*enzymology/genetics ; Glutamine/metabolism ; Hydrogen Bonding ; Isoleucine ; Molecular Structure ; *Mutation ; RNA, Transfer, Gln/metabolism ; RNA, Transfer, Tyr ; Structure-Activity Relationship ; Substrate Specificity ; Suppression, Genetic
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  • 13
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1989-05-12
    Description: The group I intron from Tetrahymena catalyzes phosphodiester transfer reactions on various RNA substrates. A modified RNA substrate with a phosphorothioate group in one stereoisomeric form at the site of reaction was synthesized in order to determine the stereochemical course of an RNA-catalyzed reaction. The reaction product was digested with a stereospecific nuclease to determine the configuration of the product phosphorothioate. The reaction occurs with inversion of configuration at phosphorus, implying an in-line pathway for the reaction.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rajagopal, J -- Doudna, J A -- Szostak, J W -- New York, N.Y. -- Science. 1989 May 12;244(4905):692-4.〈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/2470151" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Catalysis ; DNA-Directed RNA Polymerases/metabolism ; Exons ; Guanosine/metabolism ; Introns ; Molecular Conformation ; Oligonucleotides/metabolism ; Phosphorus ; RNA/chemical synthesis/metabolism ; RNA Precursors/metabolism ; RNA Splicing ; RNA, Catalytic ; RNA, Ribosomal/*metabolism ; Ribonucleases/metabolism ; Structure-Activity Relationship ; T-Phages/enzymology ; Templates, Genetic ; Tetrahymena/*genetics ; Thionucleotides/metabolism
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  • 14
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1989-03-03
    Description: Passage of proteins across membranes during export from their site of synthesis to their final destination is mediated by leader peptides that paradoxically exhibit a unity of function in spite of a diversity of sequence. These leader peptides act in at least two stages of the export process: at entry into the pathway and subsequently during translocation across the membrane. How selectivity is imposed on the system in the absence of a consensus among the sequences of leader peptides is the main issue discussed here.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Randall, L L -- Hardy, S J -- GM29798/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1989 Mar 3;243(4895):1156-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Biochemistry/Biophysics Program, Washington State University, Pullman 99164.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2646712" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Biological Transport ; Cell Membrane/*metabolism ; Escherichia coli/metabolism ; *Models, Biological ; Protein Conformation ; Protein Precursors/metabolism ; Protein Sorting Signals/*physiology ; Proteins/*metabolism ; Structure-Activity Relationship
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  • 15
    Publication Date: 1989-09-29
    Description: Synapsins are neuronal phosphoproteins that coat synaptic vesicles, bind to the cytoskeleton, and are believed to function in the regulation of neurotransmitter release. Molecular cloning reveals that the synapsins comprise a family of four homologous proteins whose messenger RNA's are generated by differential splicing of transcripts from two genes. Each synapsin is a mosaic composed of homologous amino-terminal domains common to all synapsins and different combinations of distinct carboxyl-terminal domains. Immunocytochemical studies demonstrate that all four synapsins are widely distributed in nerve terminals, but that their relative amounts vary among different kinds of synapses. The structural diversity and differential distribution of the four synapsins suggest common and different roles of each in the integration of distinct signal transduction pathways that modulate neurotransmitter release in various types of neurons.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sudhof, T C -- Czernik, A J -- Kao, H T -- Takei, K -- Johnston, P A -- Horiuchi, A -- Kanazir, S D -- Wagner, M A -- Perin, M S -- De Camilli, P -- AA 06944/AA/NIAAA NIH HHS/ -- MH 39327/MH/NIMH NIH HHS/ -- New York, N.Y. -- Science. 1989 Sep 29;245(4925):1474-80.〈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/2506642" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Base Sequence ; Molecular Sequence Data ; Nerve Tissue Proteins/*genetics ; Neuropeptides/*genetics ; Phosphoproteins/*genetics ; Sequence Homology, Nucleic Acid ; Structure-Activity Relationship ; Synapsins ; Synaptic Vesicles/*physiology
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  • 16
    Publication Date: 1989-03-17
    Description: Ornithine decarboxylase (ODC) was converted from a protein with a short intracellular half-life in mammalian cells to a stable protein by truncating 37 residues at its carboxyl terminus. Cells expressing wild-type protein lost ODC activity with a half-life of approximately 1 hour. Cells expressing the truncated protein, however, retained full activity for at least 4 hours. Pulse-chase experiments in which immunoprecipitation and gel electrophoresis were used confirmed the stabilizing effect of the truncation. Thus, a carboxyl-terminal domain is responsible for the rapid intracellular degradation of murine ODC.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ghoda, L -- van Daalen Wetters, T -- Macrae, M -- Ascherman, D -- Coffino, P -- CA 09043/CA/NCI NIH HHS/ -- CA 29048/CA/NCI NIH HHS/ -- CA 47721/CA/NCI NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1989 Mar 17;243(4897):1493-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Microbiology and Immunology, University of California, San Francisco 94143.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2928784" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Line ; Cloning, Molecular ; Mice ; Ornithine Decarboxylase/genetics/*metabolism ; Recombinant Proteins/metabolism ; Structure-Activity Relationship ; Transfection
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  • 17
    Publication Date: 1989-02-10
    Description: Signal transducing guanine nucleotide binding (G) proteins are heterotrimers with different alpha subunits that confer specificity for interactions with receptors and effectors. Eight to ten such G proteins couple a large number of receptors for hormones and neurotransmitters to at least eight different effectors. Although one G protein can interact with several receptors, a given G protein was thought to interact with but one effector. The recent finding that voltage-gated calcium channels are stimulated by purified Gs, which stimulates adenylyl cyclase, challenged this concept. However, purified Gs may have four distinct alpha-subunit polypeptides, produced by alternative splicing of messenger RNA. By using recombinant DNA techniques, three of the splice variants were synthesized in Escherichia coli and each variant was shown to stimulate both adenylyl cyclase and calcium channels. Thus, a single G protein alpha subunit may regulate more than one effector function.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Mattera, R -- Graziano, M P -- Yatani, A -- Zhou, Z -- Graf, R -- Codina, J -- Birnbaumer, L -- Gilman, A G -- Brown, A M -- DK-19318/DK/NIDDK NIH HHS/ -- HL-31164/HL/NHLBI NIH HHS/ -- HL-39262/HL/NHLBI NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1989 Feb 10;243(4892):804-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cell Biology, Baylor College of Medicine, Houston, TX 77030.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2536957" target="_blank"〉PubMed〈/a〉
    Keywords: Adenylyl Cyclases/*physiology ; Animals ; Calcium Channels/*physiology ; GTP-Binding Proteins/*genetics/physiology/ultrastructure ; In Vitro Techniques ; Macromolecular Substances ; RNA Splicing ; Structure-Activity Relationship
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  • 18
    Publication Date: 1989-06-23
    Description: A free NH2-terminal group has been previously shown to be an obligatory signal for recognition and subsequent degradation of proteins in a partially fractionated and reconstituted ubiquitin proteolytic system. Naturally occurring proteins with acetylated NH2-termini--most cellular proteins fall in this category--were not degraded by this system. Other studies have suggested that the identity of the NH2-terminal residue is important in determining the metabolic stability of a protein in vivo (N-end rule). Whole reticulocyte lysate and antibodies directed against the ubiquitin-activating enzyme (E1) have now been used to show that such acetylated proteins are degraded in a ubiquitin-dependent mode. Although fractionation of lysate does not affect its proteolytic activity toward substrates with free NH2-termini, it completely abolishes the activity toward the blocked substrates, indicating that an important component of the system was either removed or inactivated during fractionation. An NH2-terminal "unblocking" activity that removes the blocking group, thus exposing a free NH2-terminus for recognition according to the N-end rule, does not seem to participate in this pathway. Incubation of whole lysate with labeled histone H2A results in the formation of multiple ubiquitin conjugates. In contrast, the fractionated system is devoid of any significant conjugating activity. These results suggest that a novel conjugating enzyme (possibly a ubiquitin-protein ligase) may be responsible for the degradation of these acetylated proteins by recognizing structural features of the substrate that are downstream and distinct from the NH2-terminal residue.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Mayer, A -- Siegel, N R -- Schwartz, A L -- Ciechanover, A -- New York, N.Y. -- Science. 1989 Jun 23;244(4911):1480-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Unit of Biochemistry, Faculty of Medicine, Technion-Israel Institute of Technology, Haifa.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2544030" target="_blank"〉PubMed〈/a〉
    Keywords: Acetylation ; Actins/metabolism ; Adenosine Triphosphate/metabolism ; Crystallins/metabolism ; Dipeptides/pharmacology ; Electrophoresis, Polyacrylamide Gel ; Histones/metabolism ; Muramidase/metabolism ; Phosphates/metabolism ; Proteins/*metabolism ; Reticulocytes/metabolism ; Serum Albumin, Bovine/metabolism ; Structure-Activity Relationship ; Ubiquitins/*metabolism
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  • 19
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1989-02-10
    Description: A novel approach to the control of enzyme catalysis is presented in which a disulfide bond engineered into the active-site cleft of bacteriophage T4 lysozyme is capable of switching the activity on and off. Two cysteines (Thr21----Cys and Thr142----Cys) were introduced by oligonucleotide-directed mutagenesis into the active-site cleft. These cysteines spontaneously formed a disulfide bond under oxidative conditions in vitro, and the catalytic activity of the oxidized (cross-linked) T4 lysozyme was completely lost. On exposure to reducing agent, however, the disulfide bond was rapidly broken, and the reduced (non-cross-linked) lysozyme was restored to full activity. Thus an enzyme has been engineered such that redox potential can be used to control catalytic activity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Matsumura, M -- Matthews, B W -- GM21967/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1989 Feb 10;243(4892):792-4.〈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/2916125" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Chromatography, High Pressure Liquid ; DNA Mutational Analysis ; *Disulfides ; Models, Molecular ; Muramidase/*physiology ; *Protein Engineering ; Recombinant Proteins ; Structure-Activity Relationship ; T-Phages/enzymology
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  • 20
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1989-05-26
    Description: Methods for the design and synthesis of ligands intended to be specific for a metal ion have been a recent chemical development. This article describes how this process can be inverted so that the specifics of the coordination environment around the metal ion can be used as a template in large-scale ligand synthesis. The synthesis of macrobicyclic ligands for ferric ion has been accomplished by using active esters of catechol ligands in which catecholate coordination to iron is a prelude to the organic chemical reactions that link the coordination subunits together into one ligand system surrounding a central metal ion coordination site. The lanthanide(III) ions, which are among the most labile metal ions known, have coordination numbers of 8 or higher, and thus their encapsulation into a macrobicyclic structure is a challenging problem. Lanthanide amine complexes have been used as metal templates in the synthesis of such macrobicyclic lanthanide complexes. There is evidence that such a complex is inert to exchange in aqueous solution.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉McMurry, T J -- Raymond, K N -- Smith, P H -- New York, N.Y. -- Science. 1989 May 26;244(4907):938-43.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Radiation Oncology Branch, National Cancer Institute, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2658057" target="_blank"〉PubMed〈/a〉
    Keywords: Cations ; Chemical Phenomena ; Chemistry ; Iron/metabolism ; *Ligands ; Macromolecular Substances ; Metals/*metabolism ; Metals, Rare Earth/metabolism ; Molecular Structure ; Templates, Genetic
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  • 21
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1989-03-17
    Description: The adult form of Tay-Sachs disease, adult GM2 gangliosidosis, is an autosomal recessive disorder that results from mutations in the alpha chain of beta-hexosaminidase A. This disorder, like infantile Tay-Sachs disease, is more frequent in the Ashkenazi Jewish population. A point mutation in the alpha-chain gene was identified that results in the substitution of Gly with Ser in eight Ashkenazi adult GM2 gangliosidosis patients from five different families. This amino acid substitution was shown to depress drastically the catalytic activity of the alpha chain after expression in COS-1 cells. All of these patients proved to be compound heterozygotes of the allele with the Gly to Ser change and one of the two Ashkenazi infantile Tay-Sachs alleles. These findings will aid in the diagnosis and understanding of beta-hexosaminidase A deficiency disorders.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Navon, R -- Proia, R L -- New York, N.Y. -- Science. 1989 Mar 17;243(4897):1471-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Genetics and Biochemistry Branch, National Institute of Diabetes, Digestive, and Kidney Diseases, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2522679" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Base Sequence ; Cloning, Molecular ; Humans ; Jews ; Pedigree ; RNA, Messenger/genetics ; Structure-Activity Relationship ; Tay-Sachs Disease/*genetics ; beta-N-Acetylhexosaminidases/*genetics
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  • 22
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1989-02-17
    Description: Mechanistic and synthetic studies in organometallic chemistry have provided considerable insight into olefin metathesis and Ziegler-Natta polymerization. New homogeneous olefin metathesis catalysts based on high oxidation state transition metals have opened new opportunities in polymer synthesis by providing unprecedented control in ring-opening polymerization of cyclic alkenes. The recent development of living coordinative polymerization systems has led to the preparation of a number of new, interesting materials, including block copolymers, conducting polymers or precursors, and ionophoric polymeric substrates.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Grubbs, R H -- Tumas, W -- New York, N.Y. -- Science. 1989 Feb 17;243(4893):907-15.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉California Institute of Technology, Pasadena 91125.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2645643" target="_blank"〉PubMed〈/a〉
    Keywords: Chemical Phenomena ; Chemistry ; *Organometallic Compounds ; *Polymers
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  • 23
    Publication Date: 1989-09-22
    Description: The inhibition by charybdotoxin of A-type potassium channels expressed in Xenopus oocytes was studied for several splicing variants of the Drosophila Shaker gene and for several site-directed mutants of this channel. Charybdotoxin blocking affinity is lowered by a factor of 3.5 upon replacing glutamate-422 with glutamine, and by a factor of about 12 upon substituting lysine in this position. Replacement of glutamate-422 by aspartate had no effect on toxin affinity. Thus, the glutamate residue at position 422 of this potassium channel is near or in the externally facing mouth of the potassium conduction pathway, and the positively charged toxin is electrostatically focused toward its blocking site by the negative potential set up by glutamate-422.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉MacKinnon, R -- Miller, C -- AR 19826/AR/NIAMS NIH HHS/ -- GM 31768/GM/NIGMS NIH HHS/ -- NS 07292/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1989 Sep 22;245(4924):1382-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Brandeis University, Waltham, MA 02254.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2476850" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Binding Sites ; Charybdotoxin ; DNA Mutational Analysis ; Drosophila melanogaster ; Ions ; Membrane Proteins/genetics/metabolism/ultrastructure ; Potassium Channels/*metabolism/ultrastructure ; Scorpion Venoms/*metabolism ; Structure-Activity Relationship ; Transfection ; Xenopus laevis
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  • 24
    Publication Date: 1989-05-12
    Description: Calicheamicin gamma 1I is a recently discovered diyne-ene-containing antitumor antibiotic that cleaves DNA in a double-stranded fashion, a rarity among drugs, at specific sequences. It is proposed that the cutting specificity is due to a combination of the complementarity of the diyne-ene portion of the aglycone with DNA secondary structures and stabilization by association of the thiobenzoate-carbohydrate tail with the minor groove.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zein, N -- Poncin, M -- Nilakantan, R -- Ellestad, G A -- New York, N.Y. -- Science. 1989 May 12;244(4905):697-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cyanamid Company, Medical Research Division, Lederle Laboratories, Pearl River, NY 10965.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2717946" target="_blank"〉PubMed〈/a〉
    Keywords: *Aminoglycosides ; Animals ; Anti-Bacterial Agents/*metabolism ; Antibiotics, Antineoplastic ; Base Sequence ; Benzoates ; Binding Sites ; Carbohydrates ; Cattle ; Computer Simulation ; DNA/*metabolism ; Enediynes ; Models, Molecular ; Molecular Structure ; Nucleic Acid Conformation ; Structure-Activity Relationship
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  • 25
    Publication Date: 1989-03-31
    Description: The discovery that the AP-1 family of enhancer binding factors includes a complex of the cellular Fos (cFos) and cellular Jun (cJun) proteins established a direct and important link between oncogenesis and transcriptional regulation. Homodimeric cJun protein synthesized in vitro is capable of binding selectively to AP-1 recognition sites, whereas the cFos polypeptide is not. When cotranslated, the cFos and cJun proteins can form a stable, heterodimeric complex with the DNA binding properties of AP-1/cJun. The related proteins Jun B and vJun are also able to form DNA binding complexes with cFos. Directed mutagenesis of the cFos protein reveals that a leucine repeat structure is required for binding to cJun, in a manner consistent with the proposed function of the "leucine zipper." A novel domain adjacent to, but distinct from, the leucine repeat of cFos is required for DNA binding by cFos-cJun heterodimers. Thus experimental evidence is presented that leucine repeats can mediate complex formation between heterologous proteins and that promotes further understanding of the molecular mechanisms underlying the function of two proto-oncogene products.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Turner, R -- Tjian, R -- New York, N.Y. -- Science. 1989 Mar 31;243(4899):1689-94.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Department of Biochemistry, University of California, Berkeley 94720.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2494701" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Binding Sites ; Chromatography, Affinity ; DNA/*metabolism ; DNA-Binding Proteins/genetics/*metabolism ; Gene Expression Regulation ; Humans ; *Leucine ; Macromolecular Substances ; Molecular Sequence Data ; Mutation ; Oncogenes ; Protein Biosynthesis ; Proto-Oncogene Proteins/genetics/*metabolism ; Proto-Oncogene Proteins c-fos ; Proto-Oncogene Proteins c-jun ; Rats ; Repetitive Sequences, Nucleic Acid ; Structure-Activity Relationship ; Transcription Factors/genetics/*metabolism
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  • 26
    Publication Date: 1989-08-18
    Description: Oligonucleotides that bind to duplex DNA in a sequence-specific manner by triple helix formation offer an approach to the experimental manipulation of sequence-specific protein binding. Micromolar concentrations of pyrimidine oligodeoxyribonucleotides are shown to block recognition of double helical DNA by prokaryotic modifying enzymes and a eukaryotic transcription factor at a homopurine target site. Inhibition is sequence-specific. Oligonucleotides containing 5-methylcytosine provide substantially more efficient inhibition than oligonucleotides containing cytosine. The results have implications for gene-specific repression by oligonucleotides or their analogs.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Maher, L J 3rd -- Wold, B -- Dervan, P B -- New York, N.Y. -- Science. 1989 Aug 18;245(4919):725-30.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Biology, California Institute of Technology, Pasadena 91125.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2549631" target="_blank"〉PubMed〈/a〉
    Keywords: 5-Methylcytosine ; Animals ; Base Sequence ; Cytosine/analogs & derivatives ; DNA/*metabolism ; DNA Restriction Enzymes ; DNA, Recombinant ; DNA-Binding Proteins/*antagonists & inhibitors/metabolism ; Deoxyribonucleases, Type II Site-Specific/metabolism ; Metallothionein/genetics ; Methylation ; Mice ; Molecular Sequence Data ; Mutation ; Nucleic Acid Conformation ; Oligodeoxyribonucleotides/*pharmacology ; Plasmids ; Promoter Regions, Genetic ; Structure-Activity Relationship ; Transcription Factors/metabolism
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  • 27
    Publication Date: 1989-03-31
    Description: The protein products of the fos and jun proto-oncogenes form a heterodimeric complex that participates in a stable high affinity interaction with DNA elements containing AP-1 binding sites. The effects of deletions and point mutations in Fos and Jun on protein complex formation and DNA binding have been examined. The data suggest that Fos and Jun dimerize via a parallel interaction of helical domains containing a heptad repeat of leucine residues (the leucine zipper). Dimerization is required for DNA binding and results in the appropriate juxtaposition of basic amino acid regions from Fos and Jun, both of which are required for association with DNA.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gentz, R -- Rauscher, F J 3rd -- Abate, C -- Curran, T -- New York, N.Y. -- Science. 1989 Mar 31;243(4899):1695-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Oncology, Roche Institute of Molecular Biology, Nutley, NJ 07110.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2494702" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Binding Sites ; Cross-Linking Reagents ; DNA/*metabolism ; DNA-Binding Proteins/genetics/*metabolism ; Glutaral ; Immunosorbent Techniques ; *Leucine ; Macromolecular Substances ; Molecular Sequence Data ; Mutation ; Protein Conformation ; Proto-Oncogene Proteins/genetics/*metabolism ; Proto-Oncogene Proteins c-fos ; Proto-Oncogene Proteins c-jun ; Rats ; Repetitive Sequences, Nucleic Acid ; Structure-Activity Relationship ; Transcription Factors/genetics/*metabolism
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  • 28
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1989-03-17
    Description: The beta-amyloid protein is progressively deposited in Alzheimer's disease as vascular amyloid and as the amyloid cores of neuritic plaques. Contrary to its metabolically inert appearance, this peptide may have biological activity. To evaluate this possibility, a peptide ligand homologous to the first 28 residues of the beta-amyloid protein (beta 1-28) was tested in cultures of hippocampal pyramidal neurons for neurotrophic or neurotoxic effects. The beta 1-28 appeared to have neurotrophic activity because it enhanced neuronal survival under the culture conditions examined. This finding may help elucidate the sequence of events leading to plaque formation and neuronal damage in Alzheimer's disease.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Whitson, J S -- Selkoe, D J -- Cotman, C W -- AG00538/AG/NIA NIH HHS/ -- AG07918/AG/NIA NIH HHS/ -- MH19691/MH/NIMH NIH HHS/ -- New York, N.Y. -- Science. 1989 Mar 17;243(4897):1488-90.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Psychobiology, University of California, Irvine 92717.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2928783" target="_blank"〉PubMed〈/a〉
    Keywords: Amyloid/*pharmacology ; *Amyloid beta-Peptides ; *Amyloid beta-Protein Precursor ; Animals ; Cell Adhesion/drug effects ; Cell Survival ; Cells, Cultured ; Hippocampus/*cytology/embryology ; Neurons/cytology ; Peptide Fragments/*pharmacology ; Rats ; Structure-Activity Relationship
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  • 29
    Publication Date: 1989-03-17
    Description: Many diseases are dominated by persistent growth of capillary blood vessels. Tumor growth is also angiogenesis-dependent. Safe and effective angiogenesis inhibitors are needed to determine whether control of angiogenesis would be therapeutic. Heparin and certain steroids, administered together, can inhibit angiogenesis in a synergistic manner. This "pair" effect suggested that specific hydrophilic cycloamyloses may be suitable heparin substitutes. beta-Cyclodextrin tetradecasulfate administered with a steroid inhibits angiogenesis at 100 to 1000 times the effectiveness of heparin in the chick embryo bioassay. This cyclic oligosaccharide also augments the anti-angiogenic effect of angiostatic steroids against corneal neovascularization in rabbits when beta-cyclodextrin tetradecasulfate and a steroid are inserted into the cornea or applied topically as eyedrops.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Folkman, J -- Weisz, P B -- Joullie, M M -- Li, W W -- Ewing, W R -- R01-CA37395/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1989 Mar 17;243(4897):1490-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Surgery, Harvard Medical School, Boston, MA 02115.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2467380" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cyclodextrins/*pharmacology ; Dextrins/*pharmacology ; Heparin/*analogs & derivatives/pharmacology ; Heparitin Sulfate/analogs & derivatives/pharmacology ; *Neovascularization, Pathologic ; Rabbits ; Starch/*pharmacology ; Steroids/*pharmacology ; Structure-Activity Relationship
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  • 30
    Publication Date: 1989-05-12
    Description: Membrane fusion induced by the envelope glycoproteins of human and simian immunodeficiency viruses (HIV and SIVmac) is a necessary step for the infection of CD4 cells and for the formation of syncytia after infection. Identification of the region in these molecules that mediates the fusion events is important for understanding and possibly interfering with HIV/SIVmac infection and pathogenesis. Amino acid substitutions were made in the 15 NH2-terminal residues of the SIVmac gp32 transmembrane glycoprotein, and the mutants were expressed in recombinant vaccinia viruses, which were then used to infect CD4-expressing T cell lines. Mutations that increased the overall hydrophobicity of the gp32 NH2-terminus increased the ability of the viral envelope to induce syncytia formation, whereas introduction of polar or charged amino acids in the same region abolished the fusogenic function of the viral envelope. Hydrophobicity in the NH2-terminal region of gp32 may therefore be an important correlate of viral virulence in vivo and could perhaps be exploited to generate a more effective animal model for the study of acquired immunodeficiency syndrome.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bosch, M L -- Earl, P L -- Fargnoli, K -- Picciafuoco, S -- Giombini, F -- Wong-Staal, F -- Franchini, G -- New York, N.Y. -- Science. 1989 May 12;244(4905):694-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Tumor Cell Biology, National Cancer Institute, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2541505" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Base Sequence ; Cell Line ; Cloning, Molecular ; DNA, Viral/genetics ; *Gene Products, env ; HIV/*analysis ; HIV Antigens/metabolism ; HIV Envelope Protein gp120 ; HIV Envelope Protein gp41 ; Humans ; Membrane Glycoproteins ; Molecular Sequence Data ; Mutation ; *Retroviridae Proteins/genetics/metabolism/pharmacology ; *Retroviridae Proteins, Oncogenic ; Retroviruses, Simian/*analysis ; Structure-Activity Relationship ; T-Lymphocytes, Helper-Inducer/microbiology ; Transfection ; Vaccinia virus/genetics ; *Viral Envelope Proteins/genetics/metabolism/pharmacology ; *Viral Fusion Proteins
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  • 31
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1989-09-22
    Description: A plasma membrane form of guanylate cyclase is a cell surface receptor for atrial natriuretic peptide (ANP). In response to ANP binding, the receptor-enzyme produces increased amounts of the second messenger, guanosine 3',5'-monophosphate. Maximal activation of the cyclase requires the presence of adenosine 5'-triphosphate (ATP) or nonhydrolyzable ATP analogs. The intracellular region of the receptor contains at least two domains with homology to other proteins, one possessing sequence similarity to protein kinase catalytic domains, the other to regions of unknown function in a cytoplasmic form of guanylate cyclase and in adenylate cyclase. It is now shown that the protein kinase-like domain functions as a regulatory element and that the second domain possesses catalytic activity. When the kinase-like domain was removed by deletion mutagenesis, the resulting ANP receptor retained guanylate cyclase activity, but this activity was independent of ANP and its stimulation by ATP was markedly reduced. A model for signal transduction is suggested in which binding of ANP to the extracellular domain of its receptor initiates a conformational change in the protein kinase-like domain, resulting in derepression of guanylate cyclase activity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chinkers, M -- Garbers, D L -- GM31362/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1989 Sep 22;245(4924):1392-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2571188" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Atrial Natriuretic Factor/*physiology ; Cyclic GMP/physiology ; DNA Mutational Analysis ; Guanylate Cyclase/metabolism ; Magnesium/physiology ; Protein Kinases/*physiology ; Rats ; Receptors, Atrial Natriuretic Factor ; Receptors, Cell Surface/*physiology/ultrastructure ; Structure-Activity Relationship ; Transfection
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  • 32
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1989-02-03
    Description: The question of how the amino acid sequence of a protein specifies its three-dimensional structure remains to be answered. Proteins are so large and complex that it is difficult to discern the features in their sequences that contribute to their structural stability and function. One approach to this problem is de novo design of model proteins, much simpler than their natural counterparts, yet containing sufficient information in their sequences to specify a given function (for example, folding in aqueous solution, folding in membranes, or formation of ion channels). Designed proteins provide simple model systems for understanding protein structure and function.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉DeGrado, W F -- Wasserman, Z R -- Lear, J D -- New York, N.Y. -- Science. 1989 Feb 3;243(4891):622-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉E. I. du Pont de Nemours & Company, Central Research and Development Department, Wilmington, DE 19898.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2464850" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Ion Channels ; Macromolecular Substances ; Models, Molecular ; Protein Conformation ; *Proteins ; Solubility ; Structure-Activity Relationship ; Tropomyosin ; Water
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  • 33
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1989-06-02
    Description: A molecular dynamics simulation method is used to determine the contributions of individual amino acid residues and solvent molecules to free energy changes in proteins. Its application to the hemoglobin interface mutant Asp G1(99) beta----Ala shows that some of the contributions to the difference in the free energy of cooperativity are as large as 60 kilocalories (kcal) per mole. Since the overall free energy change is only -5.5 kcal/mole (versus the experimental value of -3.4 kcal/mole), essential elements of the thermodynamics are hidden in the measured results. By exposing the individual contributions, the free energy simulation provides new insights into the origin of thermodynamic changes in mutant proteins and demonstrates the role of effects beyond those usually considered in structural analyses.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gao, J -- Kuczera, K -- Tidor, B -- Karplus, M -- New York, N.Y. -- Science. 1989 Jun 2;244(4908):1069-72.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉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/2727695" target="_blank"〉PubMed〈/a〉
    Keywords: Alanine ; Asparagine ; Hemoglobins/*genetics ; Hydrogen Bonding ; Macromolecular Substances ; Molecular Structure ; *Mutation ; Oxyhemoglobins ; Structure-Activity Relationship ; Thermodynamics
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  • 34
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1989-09-22
    Description: RU 486, a steroid with high affinity for the progesterone receptor, is the first available active antiprogesterone. It has been used successfully as a medical alternative for early pregnancy interruption, and it also has other potential applications in medicine and for biochemical and pathophysiological endocrine research.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Baulieu, E E -- New York, N.Y. -- Science. 1989 Sep 22;245(4924):1351-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉INSERM U 33 (Communications hormonales), Faculte de Medicine, Universite Paris-Sud, Bicetre, France.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2781282" target="_blank"〉PubMed〈/a〉
    Keywords: Abortifacient Agents/*therapeutic use ; Abortifacient Agents, Steroidal/pharmacology/*therapeutic use ; Animals ; Drug Administration Schedule ; Embryo Implantation/drug effects ; Estrenes/administration & dosage/pharmacology/*therapeutic use ; Female ; Gene Expression Regulation/drug effects ; Glucocorticoids/antagonists & inhibitors ; Humans ; Luteinizing Hormone/secretion ; Mifepristone ; Pregnancy/drug effects ; Progesterone/*antagonists & inhibitors ; Receptors, Glucocorticoid/drug effects ; Receptors, Progesterone/*drug effects ; Structure-Activity Relationship
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  • 35
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1989-03-03
    Description: Decay accelerating factor (DAF) is anchored to the plasma membrane by a glycophospholipid (GPI) membrane anchor covalently attached to the COOH-terminus of the protein. A hydrophobic domain located at the COOH-terminus is required for anchor attachment; DAF molecules lacking this domain are secreted. Replacement of the COOH-terminal hydrophobic domain with a signal peptide that normally functions in membrane translocation, or with a random hydrophobic sequence, results in efficient and correct processing, producing GPI-anchored DAF on the cell surface. The structural requirements for GPI anchor attachment and for membrane translocation are therefore similar, presumably depending on overall hydrophobicity rather than specific sequences.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Caras, I W -- Weddell, G N -- New York, N.Y. -- Science. 1989 Mar 3;243(4895):1196-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Genentech, South San Francisco, CA 94080.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2466338" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Antigens, CD55 ; Blood Proteins ; *Carbohydrate Metabolism ; Cell Line ; Cell Membrane/*metabolism ; Complement Inactivator Proteins ; Ethanolamine ; Ethanolamines/metabolism ; Growth Hormone ; Humans ; Immunosorbent Techniques ; Membrane Proteins/genetics/*metabolism/secretion ; Mutation ; Phosphatidylinositol Diacylglycerol-Lyase ; Phosphatidylinositols/metabolism ; Phospholipids/*metabolism ; Phosphoric Diester Hydrolases/metabolism ; Protein Sorting Signals/*physiology ; Structure-Activity Relationship ; Transfection
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  • 36
    Publication Date: 1989-06-02
    Description: A strategy, called alanine-scanning mutagenesis, was used to identify specific side chains in human growth hormone (hGH) that strongly modulate binding to the hGH receptor cloned from human liver. Single alanine mutations (62 in total) were introduced at every residue contained within the three discontinuous segments of hGH (residues 2 to 19, 54 to 74, and 167 to 191) that have been implicated in receptor recognition. The alanine scan revealed a cluster of a dozen large side chains that when mutated to alanine each showed more than a four times lower binding affinity to the hGH receptor. Many of these residues that promote binding to the hGH receptor are altered in homologs of hGH (such as placental lactogens and prolactins) that do not bind tightly to the hGH receptor. The overall folding of these mutant proteins was indistinguishable from that of the wild-type hGH, as determined by strong cross-reactivities with seven different conformationally sensitive monoclonal antibodies. The alanine scan also identified at least one side chain, Glu174, that hindered binding because when it was mutated to alanine the receptor affinity increased by more than a factor of four.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cunningham, B C -- Wells, J A -- New York, N.Y. -- Science. 1989 Jun 2;244(4908):1081-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biomolecular Chemistry, Genentech, South San Francisco, CA 94080.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2471267" target="_blank"〉PubMed〈/a〉
    Keywords: *Alanine ; Amino Acid Sequence ; Antibodies, Monoclonal ; Disulfides ; Epitopes/immunology ; Growth Hormone/genetics/immunology/*metabolism ; Humans ; Hydrogen Bonding ; Molecular Sequence Data ; Molecular Structure ; *Mutation ; Placental Lactogen ; Prolactin ; Protein Conformation ; Receptors, Somatotropin/*metabolism ; Structure-Activity Relationship
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  • 37
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-09-09
    Description: Oligonucleotides complementary to regions of U1 and U2 small nuclear RNAs (snRNAs), when injected into Xenopus laevis oocytes, rapidly induced the specific degradation of U1 and U2 snRNAs, respectively, and then themselves were degraded. After such treatment, splicing of simian virus 40 (SV40) late pre-mRNA transcribed from microinjected viral DNA was blocked in oocytes. If before introduction of SV40 DNA into oocytes HeLa cell U1 or U2 snRNAs were injected and allowed to assemble into small nuclear ribonucleoprotein particle (snRNP)-like complexes, SV40 late RNA was as efficiently spliced as in oocytes that did not receive U1 or U2 oligonucleotides. This demonstrates that oocytes can form fully functional hybrid U1 and U2 snRNPs consisting of human snRNA and amphibian proteins.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pan, Z Q -- Prives, C -- CA33620/CA/NCI NIH HHS/ -- CA46121/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1988 Sep 9;241(4871):1328-31.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Sciences, Columbia University, New York, NY 10027.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2970672" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Humans ; Macromolecular Substances ; Oocytes ; *RNA Splicing ; *RNA, Small Nuclear ; *Ribonucleoproteins ; Ribonucleoproteins, Small Nuclear ; Species Specificity ; Structure-Activity Relationship ; Xenopus laevis
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  • 38
    Publication Date: 1988-12-02
    Description: Human gamma-aminobutyric acid A (GABAA) receptor subunits were expressed transiently in cultured mammalian cells. This expression system allows the simultaneous characterization of ligand-gated ion channels by electrophysiology and by pharmacology. Thus, coexpression of the alpha and beta subunits of the GABAA receptor generated GABA-gated chloride channels and binding sites for GABAA receptor ligands. Channels consisting of only alpha or beta subunits could also be detected. These homomeric channels formed with reduced efficiencies compared to the heteromeric receptors. Both of these homomeric GABA-responsive channels were potentiated by barbiturate, indicating that sites for both ligand-gating and allosteric potentiation are present on receptors assembled from either subunit.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pritchett, D B -- Sontheimer, H -- Gorman, C M -- Kettenmann, H -- Seeburg, P H -- Schofield, P R -- New York, N.Y. -- Science. 1988 Dec 2;242(4883):1306-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Molecular Neuroendocrinology, ZMBH, University of Heidelberg, Federal Republic of Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2848320" target="_blank"〉PubMed〈/a〉
    Keywords: Allosteric Regulation ; Blotting, Northern ; Cells, Cultured ; Chloride Channels ; Chlorides/*physiology ; Cloning, Molecular ; Electric Conductivity ; Humans ; Macromolecular Substances ; Membrane Proteins/*physiology ; Muscimol/metabolism ; Receptors, GABA-A/*physiology/ultrastructure ; Structure-Activity Relationship ; Transfection
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  • 39
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-08-19
    Description: The question of how the primary amino acid sequence of a protein determines its three-dimensional structure is still unanswered. One approach to this problem involves the de novo design of model peptides and proteins that should adopt desired three-dimensional structures. A systematic approach was aimed at the design of a four-helix bundle protein. The gene encoding the designed protein was synthesized and the protein was expressed in Escherichia coli and purified to homogeneity. The protein was shown to be monomeric, highly helical, and very stable to denaturation by guanidine hydrochloride (GuHCl). Thus a globular protein has been designed that is capable of adopting a stable, folded structure in aqueous solution.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Regan, L -- DeGrado, W F -- New York, N.Y. -- Science. 1988 Aug 19;241(4868):976-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉E. I. du Pont de Nemours & Company, Central Research & Development Department, Wilmington, DE 19898.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3043666" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Chemical Phenomena ; Chemistry ; Chromatography, Gel ; Escherichia coli/genetics ; Molecular Sequence Data ; Plasmids ; *Protein Conformation ; *Proteins/genetics
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  • 40
    Publication Date: 1988-09-16
    Description: In the proposed "zinc finger" DNA-binding motif, each repeat unit binds a zinc metal ion through invariant Cys and His residues and this drives the folding of each 30-residue unit into an independent nucleic acid-binding domain. To obtain structural information, we synthesized single and double zinc finger peptides from the yeast transcription activator ADR1, and assessed the metal-binding and DNA-binding properties of these peptides, as well as the solution structure of the metal-stabilized domains, with the use of a variety of spectroscopic techniques. A single zinc finger can exist as an independent structure sufficient for zinc-dependent DNA binding. An experimentally determined model of the single finger is proposed that is consistent with circular dichroism, one- and two-dimensional nuclear magnetic resonance, and visual spectroscopy of the single-finger peptide reconstituted in the presence of zinc.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Parraga, G -- Horvath, S J -- Eisen, A -- Taylor, W E -- Hood, L -- Young, E T -- Klevit, R E -- New York, N.Y. -- Science. 1988 Sep 16;241(4872):1489-92.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of Washington, Seattle 98195.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3047872" target="_blank"〉PubMed〈/a〉
    Keywords: Circular Dichroism ; DNA Mutational Analysis ; *DNA-Binding Proteins ; Magnetic Resonance Spectroscopy ; Metalloproteins ; Protein Conformation ; Saccharomyces cerevisiae ; Structure-Activity Relationship ; *Transcription Factors ; Zinc/*physiology
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  • 41
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-01-08
    Description: The Bacillus subtilis ribonuclease P consists of a protein and an RNA. At high ionic strength the reaction is protein-independent; the RNA alone is capable of cleaving precursor transfer RNA, but the turnover is slow. Kinetic analyses show that high salt concentrations facilitate substrate binding in the absence of the protein, probably by decreasing the repulsion between the polyanionic enzyme and substrate RNAs, and also slow product release and enzyme turnover. It is proposed that the ribonuclease P protein, which is small and basic, provides a local pool of counter-ions that facilitates substrate binding without interfering with rapid product release.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Reich, C -- Olsen, G J -- Pace, B -- Pace, N R -- GM34527/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Jan 8;239(4836):178-81.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, Indiana University, Bloomington 47405.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3122322" target="_blank"〉PubMed〈/a〉
    Keywords: Bacillus subtilis/*enzymology ; Endoribonucleases/*physiology ; Kinetics ; Nucleic Acid Precursors/metabolism ; RNA, Transfer/metabolism ; Ribonuclease P ; Ribonucleoproteins/*physiology ; Structure-Activity Relationship
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  • 42
    Publication Date: 1988-07-01
    Description: A method of combinatorial cassette mutagenesis was designed to readily determine the informational content of individual residues in protein sequences. The technique consists of simultaneously randomizing two or three positions by oligonucleotide cassette mutagenesis, selecting for functional protein, and then sequencing to determine the spectrum of allowable substitutions at each position. Repeated application of this method to the dimer interface of the DNA-binding domain of lambda repressor reveals that the number and type of substitutions allowed at each position are extremely variable. At some positions only one or two residues are functionally acceptable; at other positions a wide range of residues and residue types are tolerated. The number of substitutions allowed at each position roughly correlates with the solvent accessibility of the wild-type side chain.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Reidhaar-Olson, J F -- Sauer, R T -- AI-15706/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 1988 Jul 1;241(4861):53-7.〈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/3388019" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Binding Sites ; Codon ; DNA/genetics/metabolism ; *DNA-Binding Proteins ; Macromolecular Substances ; Molecular Sequence Data ; Mutation ; Plasmids ; Protein Conformation ; Repressor Proteins/*genetics ; Structure-Activity Relationship ; Transcription Factors/*genetics ; Viral Proteins ; Viral Regulatory and Accessory Proteins
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  • 43
    Publication Date: 1988-12-02
    Description: D-galactose-binding (or chemoreceptor) protein of Escherichia coli serves as an initial component for both chemotaxis towards galactose and glucose and high-affinity active transport of the two sugars. Well-refined x-ray structures of the liganded forms of the wild-type and a mutant protein isolated from a strain defective in chemotaxis but fully competent in transport have provided a molecular view of the sugar-binding site and of a site for interacting with the Trg transmembrane signal transducer. The geometry of the sugar-binding site, located in the cleft between the two lobes of the bilobate protein, is novel in that it is designed for tight binding and sequestering of either the alpha or beta anomer of the D-stereoisomer of the 4-epimers galactose and glucose. Binding specificity and affinity are conferred primarily by polar planar side-chain residues that form intricate networks of cooperative and bidentate hydrogen bonds with the sugar substrates, and secondarily by aromatic residues that sandwich the pyranose ring. Each of the pairs of anomeric hydroxyls and epimeric hydroxyls is recognized by a distinct Asp residue. The site for interaction with the transducer is about 18 A from the sugar-binding site. Mutation of Gly74 to Asp at this site, concomitant with considerable changes in the local ordered water structures, contributes to the lack of productive interaction with the transmembrane signal transducer.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Vyas, N K -- Vyas, M N -- Quiocho, F A -- New York, N.Y. -- Science. 1988 Dec 2;242(4883):1290-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3057628" target="_blank"〉PubMed〈/a〉
    Keywords: Bacterial Proteins/*ultrastructure ; Binding Sites ; *Calcium-Binding Proteins ; Carrier Proteins/*ultrastructure ; *Chemotaxis ; Computer Simulation ; DNA Mutational Analysis ; Escherichia coli ; Galactose/metabolism ; Glucose/metabolism ; Hydrogen Bonding ; Models, Molecular ; *Monosaccharide Transport Proteins ; *Periplasmic Binding Proteins ; Protein Conformation ; Structure-Activity Relationship ; X-Ray Diffraction
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  • 44
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-09-02
    Description: Study of proteins that recognize specific DNA sequences has yielded much information, but the field is still in its infancy. Already two major structural motifs have been discovered, the helix-turn-helix and zinc finger, and numerous examples of DNA-binding proteins containing either of them are known. The restriction enzyme Eco RI uses yet a different motif. Additional motifs are likely to be found as well. There is a growing understanding of some of the physical chemistry involved in protein-DNA binding, but much remains to be learned before it becomes possible to engineer a protein that binds to a specific DNA sequence.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schleif, R -- New York, N.Y. -- Science. 1988 Sep 2;241(4870):1182-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Graduate Department of Biochemistry, Brandeis University, Waltham, MA 02254.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2842864" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acids/metabolism ; Binding Sites ; Chemical Phenomena ; Chemistry ; DNA/metabolism ; DNA Restriction Enzymes/metabolism ; DNA-Binding Proteins/*metabolism ; Deoxyribonuclease EcoRI ; Electrochemistry ; Nucleic Acids/metabolism ; Protein Conformation ; Zinc
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  • 45
    Publication Date: 1988-11-11
    Description: A systematic series of low molecular weight protein tyrosine kinase inhibitors were synthesized; they had progressively increasing affinity over a 2500-fold range toward the substrate site of epidermal growth factor (EGF) receptor kinase domain. These compounds inhibited EGF receptor kinase activity up to three orders of magnitude more than they inhibited insulin receptor kinase, and they also effectively inhibited the EGF-dependent autophosphorylation of the receptor. The most potent compounds effectively inhibited the EGF-dependent proliferation of A431/clone 15 cells with little or no effect on the EGF-independent proliferation of these cells. The potential use of tyrosine protein kinase inhibitors as antiproliferative agents is demonstrated.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Yaish, P -- Gazit, A -- Gilon, C -- Levitzki, A -- New York, N.Y. -- Science. 1988 Nov 11;242(4880):933-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Chemistry, Hebrew University of Jerusalem, Israel.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3263702" target="_blank"〉PubMed〈/a〉
    Keywords: Binding, Competitive ; Cell Division/drug effects ; Cell Line ; Epidermal Growth Factor/*pharmacology ; Molecular Structure ; Molecular Weight ; Phosphorylation ; Protein-Tyrosine Kinases/*antagonists & inhibitors ; Receptor, Epidermal Growth Factor/*metabolism ; Receptor, Insulin/metabolism ; Solubility ; Structure-Activity Relationship
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  • 46
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-06-24
    Description: A specific, reversible binding site for a free amino acid is detectable on the intron of the Tetrahymena self-splicing ribosomal precursor RNA. The site selects arginine among the natural amino acids, and prefers the L- to the D-amino acid. The dissociation constant is in the millimolar range, and amino acid binding is at or in the catalytic rG splicing substrate site. Occupation of the G site by L-arginine therefore inhibits splicing by inhibiting the binding of rG, without inhibition of later reactions in the splicing reaction sequence. Arginine binding specificity seems to be directed at the side chain and the guanidino radical, and the alpha-amino and carboxyl groups are dispensable for binding. The arginine site can be placed within the G site by structural homology, with consequent implications for RNA-amino acid interaction, for the origin of the genetic code, for control of RNA activities, and for further catalytic capabilities for RNA.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Yarus, M -- R37 GM30881/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Jun 24;240(4860):1751-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder 80309.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3381099" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Arginine/*metabolism ; Binding Sites ; Catalysis ; Genetic Code ; Guanosine Triphosphate/metabolism ; Kinetics ; Magnesium/metabolism ; Models, Molecular ; *RNA Splicing ; RNA, Ribosomal/*physiology ; Structure-Activity Relationship ; Tetrahymena
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  • 47
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-06-24
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Marx, J L -- New York, N.Y. -- Science. 1988 Jun 24;240(4860):1732.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3381097" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; *DNA-Binding Proteins ; Leucine ; Structure-Activity Relationship
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  • 48
    Publication Date: 1988-07-22
    Description: The alpha subunits of Gs and Gi link different sets of hormone receptors to stimulation and inhibition, respectively, of adenylyl cyclase. A chimeric alpha i/alpha s cDNA was constructed that encodes a polypeptide composed of the amino terminal 60% of an alpha i chain and the carboxyl terminal 40% of alpha s. The cDNA was introduced via a retroviral vector into S49 cyc- cells, which lack endogenous alpha s. Although less than half of the hybrid alpha chain is derived from alpha s, its ability to mediate beta-adrenoceptor stimulation of adenylyl cyclase matched that of the normal alpha s polypeptide expressed from the same retroviral vector in cyc- cells. This result indicates that carboxyl terminal amino acid sequences of alpha s contain the structural features that are required for specificity of interactions with the effector enzyme, adenylyl cyclase, as well as with the hormone receptor.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Masters, S B -- Sullivan, K A -- Miller, R T -- Beiderman, B -- Lopez, N G -- Ramachandran, J -- Bourne, H R -- New York, N.Y. -- Science. 1988 Jul 22;241(4864):448-51.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pharmacology, University of California, San Francisco 94143.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2899356" target="_blank"〉PubMed〈/a〉
    Keywords: Adenylyl Cyclases/*physiology ; Animals ; Cell Line ; Cell Membrane/physiology ; Cholera Toxin/pharmacology ; Colforsin/pharmacology ; Enzyme Activation ; GTP-Binding Proteins/*physiology ; Guanosine Triphosphate/pharmacology ; Isoproterenol/pharmacology ; Mice ; Receptors, Adrenergic, beta/*physiology ; Recombinant Proteins ; Somatostatin/pharmacology ; Structure-Activity Relationship
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  • 49
    Publication Date: 1988-12-23
    Description: The aminoacylation specificity ("acceptor identity") of transfer RNAs (tRNAs) has previously been associated with the position of particular nucleotides, as opposed to distinctive elements of three-dimensional structure. The contribution of a G.U wobble pair in the acceptor helix of tRNA(Ala) to acceptor identity was examined with synthetic amber suppressor tRNAs in Escherichia coli. The acceptor identity was not affected by replacing the G.U wobble pair in tRNA(Ala) with a G.A, C.A, or U.U wobble pair. Furthermore, a tRNA(Ala) acceptor identity was conferred on tRNA(Lys) when the same site in the acceptor helix was replaced with any of several wobble pairs. Additional data with tRNA(Ala) show that a substantial acceptor identity was retained when the G.U wobble pair was translocated to another site in the acceptor helix. These results suggest that the G.U wobble pair induces an irregularity in the acceptor helix of tRNA(Ala) to match a complementary structure in the aminoacylating enzyme.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉McClain, W H -- Chen, Y M -- Foss, K -- Schneider, J -- GM42123/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Dec 23;242(4886):1681-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Bacteriology, University of Wisconsin, Madison 53706.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2462282" target="_blank"〉PubMed〈/a〉
    Keywords: Base Composition ; Escherichia coli/*genetics ; Mutation ; *Nucleic Acid Conformation ; RNA, Bacterial/*metabolism ; RNA, Transfer, Ala/*metabolism ; RNA, Transfer, Amino Acid-Specific/*metabolism ; Structure-Activity Relationship ; Suppression, Genetic
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  • 50
    Publication Date: 1988-11-18
    Description: A general chemical strategy has been developed whereby antibody combining sites can be selectively derivatized with natural or synthetic molecules, such as catalytic groups, drugs, metals, or reporter molecules. Cleavable affinity labels were used to selectively introduce a thiol into the combining site of the immunoglobulin A MOPC 315. This thiol acted both as a nucleophile to accelerate ester thiolysis 60,000-fold and as a handle for selectively derivatizing the antibody with additional functional groups. For example, derivatization of the antibody with a fluorophore made possible a direct spectroscopic assay of antibody-ligand complexation. This chemistry should not only extend our ability to exploit antibody specificity in chemical catalysis, diagnostics, and therapeutics, but may also prove generally applicable to the functional modification of other proteins for which detailed structural information is unavailable.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pollack, S J -- Nakayama, G R -- Schultz, P G -- AI24695-02/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 1988 Nov 18;242(4881):1038-40.〈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/3194752" target="_blank"〉PubMed〈/a〉
    Keywords: Affinity Labels ; Animals ; *Antigen-Antibody Reactions ; *Binding Sites, Antibody ; Chemical Phenomena ; Chemistry ; Dinitrobenzenes ; Immunoglobulin Fab Fragments ; Mice ; Spectrometry, Fluorescence ; Sulfhydryl Compounds
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  • 51
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-06-24
    Description: Epidermal growth factor (EGF) is a well-characterized polypeptide hormone with diverse biological activities, including stimulation of astrocyte division. A soluble astrocyte mitogen inhibitor, immunologically related to the EGF receptor, is present in rat brain. Injury to the brain causes a time-dependent reduction in the levels of this inhibitor and the concomitant appearance of EGF receptor on the astrocyte surface. Intracerebral injection of antibody capable of binding the inhibitor caused the appearance of numerous reactive astrocytes. EGF receptor-related inhibitors may play a key role in the control of glial cell division in both normal and injured brain.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nieto-Sampedro, M -- AG 00538-09A/AG/NIA NIH HHS/ -- New York, N.Y. -- Science. 1988 Jun 24;240(4860):1784-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Psychobiology, University of California, Irvine 92717.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3289118" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Astrocytes/*physiology ; Brain Injuries/*physiopathology ; Cell Division ; Cross Reactions ; Immunologic Techniques ; Rats ; Receptor, Epidermal Growth Factor/*antagonists & inhibitors/immunology ; Receptors, Mitogen/*antagonists & inhibitors ; Structure-Activity Relationship ; Time Factors
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  • 52
    Publication Date: 1988-04-22
    Description: A cytoplasmic protein that greatly enhances the guanosine triphosphatase (GTPase) activity of N-ras protein but does not affect the activity of oncogenic ras mutants has been recently described. This protein (GAP) is shown here to be ubiquitous in higher eukaryotes and to interact with H-ras as well as with N-ras proteins. To identify the region of ras p21 with which GAP interacts, 21 H-ras mutant proteins were purified and tested for their ability to undergo stimulation of GTPase activity by GAP. Mutations in nonessential regions of H-ras p21 as well as mutations in its carboxyl-terminal domain (residues 165-185) and purine binding region (residues 117 and 119) did not decrease the ability of the protein to respond to GAP. In addition, an antibody against the carboxyl-terminal domain did not block GAP activity, supporting the conclusion that GAP does not interact with this region. Transforming mutations at positions 12, 59, and 61 (the phosphoryl binding region) abolished GTPase stimulation by GAP. Point mutations in the putative effector region of ras p21 (amino acids 35, 36, and 38) were also insensitive to GAP. However, a point mutation at position 39, shown previously not to impair effector function, did not alter GAP-p21 interaction. These results indicate that GAP interaction may be essential for ras p21 biological activity and that it may be a ras effector protein.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Adari, H -- Lowy, D R -- Willumsen, B M -- Der, C J -- McCormick, F -- New York, N.Y. -- Science. 1988 Apr 22;240(4851):518-21.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Cetus Corporation, Emeryville, CA 94608.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2833817" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Antibodies, Monoclonal/immunology ; DNA Mutational Analysis ; Enzyme Activation ; GTP Phosphohydrolases/*metabolism ; GTP-Binding Proteins/*metabolism ; GTPase-Activating Proteins ; *Genes, ras ; Immunologic Techniques ; In Vitro Techniques ; Phosphoric Monoester Hydrolases/*metabolism ; Proteins/*metabolism ; Proto-Oncogene Proteins/*metabolism ; Structure-Activity Relationship ; ras GTPase-Activating Proteins
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  • 53
    Publication Date: 1988-01-22
    Description: Overexpression of the cellular src gene in NIH 3T3 cells causes reduction of cell-to-cell transmission of molecules in the 400- to 700-dalton range. This down-regulation of gap junctional communication correlates with the activity of the gene product, the protein tyrosine kinase pp60c-src. The down-regulation was enhanced by point mutation of Tyr527 (a site that is phosphorylated in pp60c-src and that inhibits kinase activity) or by substitution of the viral-src for the cellular-src carboxyl-terminal coding region. Mutation of Tyr416 (a site phosphorylated upon Tyr527 mutation) suppresses both the down-regulation of communication by Tyr527 mutation and that by gene overexpression. The regulation of communication by src may be important in the control of embryonic development and cellular growth.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Azarnia, R -- Reddy, S -- Kmiecik, T E -- Shalloway, D -- Loewenstein, W R -- CA-14464/CA/NCI NIH HHS/ -- CA-32317/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1988 Jan 22;239(4838):398-401.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology and Biophysics, University of Miami School of Medicine, FL 33136.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2447651" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Cell Communication ; Cell Line ; Cell Membrane Permeability ; Gene Expression Regulation ; *Intercellular Junctions ; Mice ; Mutation ; Phosphorylation ; Plasmids ; Protein-Tyrosine Kinases/*genetics ; Proto-Oncogene Proteins/genetics/*physiology ; Proto-Oncogene Proteins pp60(c-src) ; Structure-Activity Relationship ; Transcription, Genetic ; Transfection ; Tyrosine/metabolism
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  • 54
    Publication Date: 1988-03-04
    Description: Kinetic analysis and protein mutagenesis allow the importance of individual amino acids in ligand binding and catalysis to be assessed. A kinetic analysis has shown that the reaction catalyzed by dihydrofolate reductase is optimized with respect to product flux, which in turn is predetermined by the active-site hydrophobic surface. Protein mutagenesis has revealed that specific hydrophobic residues contribute 2 to 5 kilocalories per mole to ligand binding and catalysis. The extent to which perturbations within this active-site ensemble may affect catalysis is discussed in terms of the constraints imposed by the energy surface for the reaction.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Benkovic, S J -- Fierke, C A -- Naylor, A M -- GM24129/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Mar 4;239(4844):1105-10.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Pennsylvania State University, University Park 16802.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3125607" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Catalysis ; Chemical Phenomena ; Chemistry ; Escherichia coli/enzymology ; Kinetics ; Lactobacillus casei/enzymology ; *Mutation ; Structure-Activity Relationship ; Tetrahydrofolate Dehydrogenase/genetics/*metabolism ; Thermodynamics
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  • 55
    Publication Date: 1988-10-28
    Description: The alpha and beta subunits of the gamma-aminobutyric acidA (GABAA) receptor were expressed individually in Xenopus oocytes by injection of RNA synthesized from their cloned DNAs. GABA-sensitive chloride channels were detected several days after injection with any one of three different alpha RNAs (alpha 1, alpha 2, and alpha 3) or with beta RNA. The channels induced by each of the alpha-subunit RNAs were indistinguishable, they had multiple conductance levels (10, 19, 28, and 42 picosiemens), and their activity was potentiated by pentobarbital and inhibited by picrotoxin. The beta channels usually expressed poorly but showed similar single channel conductance levels (10, 18, 27, and 40 picosiemens), potentiation by pentobarbital and inhibition by picrotoxin. The finding that both alpha and beta subunits, examined separately, form GABA-sensitive ion channels with permeation properties and regulatory sites characteristic of the native receptor suggests that the amino acid sequences that confer these properties are within the homologous domains shared by the subunits.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Blair, L A -- Levitan, E S -- Marshall, J -- Dionne, V E -- Barnard, E A -- NS20962/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1988 Oct 28;242(4878):577-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉MRC Molecular Neurobiology Unit, University of Cambridge, United Kingdom.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2845583" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Chloride Channels ; Chlorides/*physiology ; Cloning, Molecular ; Dose-Response Relationship, Drug ; Electric Conductivity ; Macromolecular Substances ; Membrane Proteins/*physiology ; Picrotoxin/pharmacology ; RNA, Messenger/administration & dosage ; Receptors, GABA-A/*physiology ; Structure-Activity Relationship ; Xenopus laevis ; gamma-Aminobutyric Acid/pharmacology
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  • 56
    Publication Date: 1988-12-23
    Description: Homozygous inheritance of the Z-type mutant form of the alpha 1-antitrypsin (alpha 1AT) gene results in the most common form of alpha 1AT deficiency, a human hereditary disease associated with a high risk for the development of emphysema and an increased incidence of neonatal hepatitis. The alpha 1AT-synthesizing cells of individuals with the Z gene have normal alpha 1AT messenger RNA levels, but alpha 1AT secretion is markedly reduced secondary to accumulation of newly synthesized alpha 1AT in the rough endoplasmic reticulum. Crystallographic analysis of alpha 1AT predicts that in normal alpha 1AT, a negatively charged Glu342 is adjacent to positively charged Lys290. Thus the Glu342----Lys342 Z mutation caused the loss of a normal salt bridge, resulting in the intracellular aggregation of the Z molecule. The prediction was made that a second mutation in the alpha 1AT genet that changed the positively charged Lys290 to a negatively charged Glu290 would correct the secretion defect. When the second mutation was added to the Z-type complementary DNA, the resulting gene directed the synthesis and secretion of amounts of alpha 1AT similar to that directed by the normal alpha 1AT complementary DNA in an in vitro eukaryotic expression system. This suggests the possibility that a human hereditary disease can be corrected by inserting an additional mutation in the same gene.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Brantly, M -- Courtney, M -- Crystal, R G -- New York, N.Y. -- Science. 1988 Dec 23;242(4886):1700-2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Pulmonary Branch, National Heart, Lung, and Blood Institute, Bethesda, MD.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2904702" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Line ; Codon ; DNA/genetics ; Electrochemistry ; Endoplasmic Reticulum/metabolism ; Glutamates ; Glutamic Acid ; Humans ; Lysine ; *Mutation ; Protein Conformation ; RNA, Messenger/metabolism ; Structure-Activity Relationship ; Transfection ; alpha 1-Antitrypsin/*genetics/secretion ; alpha 1-Antitrypsin Deficiency
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  • 57
    Publication Date: 1988-01-01
    Description: Follicle-stimulating hormone (FSH) is a glycoprotein essential for gonadal development and steroidogenesis. Recent studies suggest that deglycosylation of FSH results in the formation of antagonistic proteins that are capable of binding to gonadal receptors but that are devoid of bioactivity. Treatment of hypogonadal women with an antagonist of gonadotropin-releasing hormone substantially decreased serum FSH bioactivity with minimal changes in immunoreactivity. Chromatofocusing and size fractionation of the serum samples indicated the secretion of immunoreactive FSH isoforms that are devoid of bioactivity but that are capable of blocking FSH action in ovarian granulosa cells. These findings provide the first demonstration of naturally occurring circulating antihormones. These FSH antagonists may play an important role in the physiology and pathophysiology of the gonads.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Dahl, K D -- Bicsak, T A -- Hsueh, A J -- HD-06875/HD/NICHD NIH HHS/ -- HD-06939/HD/NICHD NIH HHS/ -- HD-23273/HD/NICHD NIH HHS/ -- New York, N.Y. -- Science. 1988 Jan 1;239(4835):72-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Reproductive Medicine, University of California, San Diego, La Jolla 92093.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3122320" target="_blank"〉PubMed〈/a〉
    Keywords: Biological Assay ; Cross Reactions ; Female ; Follicle Stimulating Hormone/*antagonists & inhibitors/immunology/metabolism ; Glycoproteins/physiology ; Gonadotropin-Releasing Hormone/*antagonists & inhibitors ; Humans ; Isoelectric Point ; Radioligand Assay ; Structure-Activity Relationship
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  • 58
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-01-15
    Description: The MotB protein of Escherichia coli is an essential component of the force generators that couple proton movement across the cytoplasmic membrane to rotation of the flagellar motors. The membrane topology of MotB was examined to explore the possibility that it might form a proton channel. MotB--alkaline phosphatase fusion proteins were constructed to identify likely periplasmic domains of the MotB molecule. Fusions distal to a putative membrane-spanning segment near the amino terminus of MotB exhibited alkaline phosphatase activity, indicating that an extensive carboxyl-terminal portion of MotB may be located on the periplasmic side of the membrane. Protease treatment of MotB in spheroplasts confirmed this view. The simple transmembrane organization of MotB is difficult to reconcile with a role as a proton conductor.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chun, S Y -- Parkinson, J S -- GM19559/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Jan 15;239(4837):276-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Biology Department, University of Utah, Salt Lake City 84112.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2447650" target="_blank"〉PubMed〈/a〉
    Keywords: Alkaline Phosphatase/metabolism ; Bacterial Proteins/genetics/*metabolism ; Cell Membrane/*metabolism ; Cell Movement ; Escherichia coli/*metabolism ; Flagella/metabolism ; Ion Channels/metabolism ; Membrane Proteins/metabolism ; Peptide Fragments/metabolism ; Recombinant Fusion Proteins/metabolism ; Serine Endopeptidases/metabolism ; Structure-Activity Relationship ; Trypsin/metabolism
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  • 59
    Publication Date: 1988-09-02
    Description: Catalysis of amide bond hydrolysis is of singular importance in enzymology. An antibody was induced to an analog of a high-energy intermediate anticipated along the reaction coordinate of amide hydrolysis. This antibody is an amidase with high specificity and a large rate enhancement (250,000) relative to the uncatalyzed reaction. This reaction represents the kinetically most difficult hydrolysis reaction yet catalyzed by an antibody.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Janda, K D -- Schloeder, D -- Benkovic, S J -- Lerner, R A -- New York, N.Y. -- Science. 1988 Sep 2;241(4870):1188-91.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Research Institute of Scripps Clinic, La Jolla, CA 92037.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3413482" target="_blank"〉PubMed〈/a〉
    Keywords: Amidohydrolases/metabolism ; Animals ; Antibodies, Monoclonal/biosynthesis/*physiology ; Antibody Specificity ; Antigens/immunology ; *Catalysis ; Chemical Phenomena ; Chemistry ; Hemocyanin/analogs & derivatives/immunology ; Hydrolysis ; Immunization ; Kinetics ; Mice ; Organophosphorus Compounds/immunology ; Substrate Specificity
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  • 60
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-09-30
    Description: Homopurine-homopyrimidine sequences that flank certain actively transcribed genes are hypersensitive to single strand-specific nucleases such as S1. This has raised the possibility that an unusual structure exists in these regions that might be involved in recognition or regulation. Several of these sequences, including d(C-T)n.d(A-G)n, are known to undergo a transition in plasmids to an underwound state that is hypersensitive to single strand-specific nucleases; this transition occurs under conditions of moderately acid pH and negative supercoiling. Chemical probes were used to examine the reactivity of a restriction fragment from a human U1 gene containing the sequence d(C-T)18.d(A-G)18 as a function of supercoiling and pH, and thus analyze the structure in this region. Hyperreactivity was seen in the center and at one end of the (C-T)n tract, and continuously from the center to the same end of the (A-G)n tract, in the presence of supercoiling and pH less than or equal to 6.0. These results provide strong support for a triple-helical model recently proposed for these sequences and are inconsistent with other proposed structures.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Johnston, B H -- New York, N.Y. -- Science. 1988 Sep 30;241(4874):1800-4.〈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/2845572" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Chemical Phenomena ; Chemistry ; *Dna ; DNA, Superhelical ; Endonucleases/*metabolism ; Hydrogen-Ion Concentration ; Molecular Sequence Data ; *Nucleic Acid Conformation ; Plasmids ; Single-Strand Specific DNA and RNA Endonucleases
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  • 61
    Publication Date: 1988-06-24
    Description: A 30-amino-acid segment of C/EBP, a newly discovered enhancer binding protein, shares notable sequence similarity with a segment of the cellular Myc transforming protein. Display of these respective amino acid sequences on an idealized alpha helix revealed a periodic repetition of leucine residues at every seventh position over a distance covering eight helical turns. The periodic array of at least four leucines was also noted in the sequences of the Fos and Jun transforming proteins, as well as that of the yeast gene regulatory protein, GCN4. The polypeptide segments containing these periodic arrays of leucine residues are proposed to exist in an alpha-helical conformation, and the leucine side chains extending from one alpha helix interdigitate with those displayed from a similar alpha helix of a second polypeptide, facilitating dimerization. This hypothetical structure is referred to as the "leucine zipper," and it may represent a characteristic property of a new category of DNA binding proteins.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Landschulz, W H -- Johnson, P F -- McKnight, S L -- New York, N.Y. -- Science. 1988 Jun 24;240(4860):1759-64.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Embryology, Carnegie Institution of Washington, Baltimore, MD 21210.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3289117" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Computer Simulation ; *DNA-Binding Proteins ; *Enhancer Elements, Genetic ; *Leucine ; Models, Molecular ; Protein Conformation ; Proto-Oncogene Proteins ; Structure-Activity Relationship
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  • 62
    Publication Date: 1988-04-01
    Description: A mutant catalytic subunit of adenosine 3',5'-monophosphate (cAMP)-dependent protein kinase has been isolated from Saccharomyces cerevisiae that is no longer subject to regulation yet retains its catalytic activity. Biochemical analysis of the mutant subunit indicates a 100-fold decreased affinity for the regulatory subunit. The mutant catalytic subunit exhibits approximately a threefold increase in Michaelis constant for adenosine triphosphate and peptide cosubstrates, and is essentially unchanged in its catalytic rate. The nucleotide sequence of the mutant gene contains a single nucleotide change resulting in a threonine-to-alanine substitution at amino acid 241. This residue is conserved in other serine-threonine protein kinases. These results identify this threonine as an important contact between catalytic and regulatory subunits but only a minor contact in substrate recognition.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Levin, L R -- Kuret, J -- Johnson, K E -- Powers, S -- Cameron, S -- Michaeli, T -- Wigler, M -- Zoller, M J -- GM33986/GM/NIGMS NIH HHS/ -- R35 CA39829-02/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1988 Apr 1;240(4848):68-70.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cold Spring Harbor Laboratory, NY 11724.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2832943" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Catalysis ; Cyclic AMP/*pharmacology ; Genes, Fungal ; Kinetics ; Macromolecular Substances ; Molecular Sequence Data ; Mutation ; Phosphorylation ; Protein Kinases/*genetics/metabolism ; Saccharomyces cerevisiae/enzymology/*genetics ; Structure-Activity Relationship ; Threonine
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  • 63
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-01-15
    Description: Glycosylated forms of phosphatidylinositol, which have only recently been described in eukaryotic organisms, are now known to play important roles in biological membrane function. These molecules can serve as the sole means by which particular cell-surface proteins are anchored to the membrane. Lipids with similar structures may also be involved in signal transduction mechanisms for the hormone insulin. The utilization of this novel class of lipid molecules for these two distinct functions suggests new mechanisms for the regulation of proteins in biological membranes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Low, M G -- Saltiel, A R -- DK33804/DK/NIDDK NIH HHS/ -- GM35873/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Jan 15;239(4837):268-75.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons of Columbia University, New York, NY 10032.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3276003" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Membrane/*physiology ; Chemical Phenomena ; Chemistry ; Glycolipids/biosynthesis/*physiology ; Glycosylation ; Humans ; Hydrolysis ; Insulin/physiology ; Membrane Lipids/physiology ; Membrane Proteins/physiology ; Phosphatidylinositols/biosynthesis/*physiology ; Phospholipases/metabolism ; Phospholipid Ethers/biosynthesis/physiology ; Trypanosoma brucei brucei/metabolism
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  • 64
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-07-22
    Description: Diets rich in fish and fish oils are associated with a reduced risk of cardiovascular disease and atherosclerosis. The interaction of a commercial fish oil extract (MaxEPA) with vascular endothelial cells (ECs) was studied as a possible mechanism for this protective effect. MaxEPA almost completely inhibited EC production of platelet-derived growth factor-like protein (PDGFc) while other lipids had a lesser effect or no effect. Overall protein synthesis was not reduced, nor was the inhibition due to defective secretion or increased degradation of the growth factor. Antioxidants suppressed the inhibitory activity of MaxEPA indicating that free radical oxidative processes were required for the inhibition. These results suggest that fish oils may suppress intimal smooth muscle cell proliferation by decreasing the production of EC-derived paracrine growth factors. This inhibitory process represents a possible molecular mechanism for the antiatherosclerotic action of marine lipids.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fox, P L -- DiCorleto, P E -- HL1561/HL/NHLBI NIH HHS/ -- HL29582/HL/NHLBI NIH HHS/ -- HL40352/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1988 Jul 22;241(4864):453-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Brain and Vascular Research, Cleveland Clinic Research Institute, OH 44195.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3393911" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cattle ; Cells, Cultured ; Endothelium, Vascular/*physiology ; Fatty Acids, Unsaturated/pharmacology ; Fish Oils/*pharmacology ; In Vitro Techniques ; Oxidation-Reduction ; Platelet-Derived Growth Factor/*biosynthesis ; Structure-Activity Relationship
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  • 65
    Publication Date: 1988-04-22
    Description: The three-dimensional structure of most enzymes is unknown; however, many enzymes may have structural motifs similar to those in the known structures of functionally related enzymes. Evidence is presented that an enzyme of unknown structure [Ile-transfer RNA (tRNA) synthetase] may share a functionally important structural motif with an enzyme of related function (Tyr-tRNA synthetase). This approach involves (i) identifying segments of Ile-tRNA synthetase that have been unusually conserved during evolution, (ii) predicting the function of one such segment by assuming a structural relation between Ile-tRNA synthetase and Tyr-tRNA synthetase, and (iii) testing the predicted function by mutagenesis and subsequent biochemical analysis. Random mutations were introduced by cassette mutagenesis into a ten-amino-acid segment of Ile-tRNA synthetase that was predicted to be involved in the formation of the binding site for isoleucine. Few amino acid substitutions appear to be tolerated in this region. However, one substitution (independently isolated twice) increased the Michaelis constant Km for isoleucine in the adenylate synthesis reaction by greater than 6000-fold, but had little effect on the Km for adenosine triphosphate, the apparent Km for tRNA, or the rate constant kcat.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Clarke, N D -- Lien, D C -- Schimmel, P -- GM15539/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Apr 22;240(4851):521-3.〈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/3282306" target="_blank"〉PubMed〈/a〉
    Keywords: *Amino Acyl-tRNA Synthetases ; Binding Sites ; DNA Mutational Analysis ; Escherichia coli/enzymology ; *Isoleucine-tRNA Ligase ; Kinetics ; Protein Conformation ; Saccharomyces cerevisiae/enzymology ; Structure-Activity Relationship
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  • 66
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-05-06
    Description: The origins, definitions, tools, and guiding principles of host-guest chemistry are developed. Perching, nesting, and capsular complexes are exemplified through molecular model and crystal structure comparisons. The degree of preorganization of a host for binding is a central determinant of its binding power. Complementarity of binding site placement in host and guest is a central determinant of structural recognition in complexation. Examples are given of chiral recognition in complexation, of partial transacylase mimics, of caviplexes, and of a synthetic molecular cell.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cram, D J -- New York, N.Y. -- Science. 1988 May 6;240(4853):760-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry and Biochemistry, University of California, Los Angeles 90024.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3283937" target="_blank"〉PubMed〈/a〉
    Keywords: Acylation ; Binding Sites ; Chemical Phenomena ; Chemistry ; Crystallization ; Enzymes ; *Models, Chemical ; Models, Molecular ; Nucleic Acids ; Thermodynamics
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  • 67
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-04-22
    Description: Structural factors that influence functional properties are examined in the case of four heme enzymes: cytochrome P-450, chloroperoxidase, horseradish peroxidase, and secondary amine mono-oxygenase. The identity of the axial ligand, the nature of the heme environment, and the steric accessibility of the heme iron and heme edge combine to play major roles in determining the reactivity of each enzyme. The importance of synthetic porphyrin models in understanding the properties of the protein-free metal center is emphasized. The conclusions described herein have been derived from studies at the interface between biological and inorganic chemistry.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Dawson, J H -- AM 01123/AM/NIADDK NIH HHS/ -- GM-26730/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Apr 22;240(4851):433-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of South Carolina, Columbia 29208.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3358128" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; Chloride Peroxidase ; Cytochrome P-450 Enzyme System ; *Hemeproteins ; Horseradish Peroxidase ; *Oxygenases ; *Peroxidases ; Structure-Activity Relationship
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  • 68
    Publication Date: 1988-04-08
    Description: Site-directed mutagenesis of the large fragment of DNA polymerase I (Klenow fragment) yielded two mutant proteins lacking 3',5'-exonuclease activity but having normal polymerase activity. Crystallographic analysis of the mutant proteins showed that neither had any alteration in protein structure other than the expected changes at the mutation sites. These results confirmed the presumed location of the exonuclease active site on the small domain of Klenow fragment and its physical separation from the polymerase active site. An anomalous scattering difference Fourier of a complex of the wild-type enzyme with divalent manganese ion and deoxythymidine monophosphate showed that the exonuclease active site has binding sites for two divalent metal ions. The properties of the mutant proteins suggest that one metal ion plays a role in substrate binding while the other is involved in catalysis of the exonuclease reaction.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Derbyshire, V -- Freemont, P S -- Sanderson, M R -- Beese, L -- Friedman, J M -- Joyce, C M -- Steitz, T A -- GM-22778/GM/NIGMS NIH HHS/ -- GM-28550/GM/NIGMS NIH HHS/ -- RR-01644/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 1988 Apr 8;240(4849):199-201.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biophysics and Biochemistry, Yale University Medical School, New Haven, CT 06510.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2832946" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Catalysis ; Computer Graphics ; Crystallography ; DNA Mutational Analysis ; *DNA Polymerase I/genetics ; Escherichia coli/enzymology ; Exonucleases ; Metals ; Models, Molecular ; Protein Conformation ; Structure-Activity Relationship
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  • 69
    Publication Date: 1988-09-16
    Description: A hybrid protein between interferon-gamma and tumor necrosis factor-beta was made by ligating the respective genes and expressing the fused genes under the control of the trp promoter in Escherichia coli. The antiproliferative activity of the hybrid protein in vitro was greatly increased compared with either interferon-gamma or tumor necrosis factor-beta alone, and both antiviral activity and cytotoxic effect were retained in the hybrid protein. The hybrid protein may have potential clinical application.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Feng, G S -- Gray, P W -- Shepard, H M -- Taylor, M W -- AI21898/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 1988 Sep 16;241(4872):1501-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, Indiana University, Bloomington 47405.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3138754" target="_blank"〉PubMed〈/a〉
    Keywords: *Antiviral Agents ; Cloning, Molecular ; *Growth Inhibitors ; Immunosorbent Techniques ; *Interferon-gamma ; Recombinant Fusion Proteins/pharmacology ; Structure-Activity Relationship ; *Tumor Necrosis Factor-alpha
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  • 70
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-04-29
    Description: Exposure of Escherichia coli to low concentrations of hydrogen peroxide results in DNA damage that causes mutagenesis and kills the bacteria, whereas higher concentrations of peroxide reduce the amount of such damage. Earlier studies indicated that the direct DNA oxidant is a derivative of hydrogen peroxide whose formation is dependent on cell metabolism. The generation of this oxidant depends on the availability of both reducing equivalents and an iron species, which together mediate a Fenton reaction in which ferrous iron reduces hydrogen peroxide to a reactive radical. An in vitro Fenton system was established that generates DNA strand breaks and inactivates bacteriophage and that also reproduces the suppression of DNA damage by high concentrations of peroxide. The direct DNA oxidant both in vivo and in this in vitro system exhibits reactivity unlike that of a free hydroxyl radical and may instead be a ferryl radical.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Imlay, J A -- Chin, S M -- Linn, S -- GM19020/GM/NIGMS NIH HHS/ -- P30ES01896/ES/NIEHS NIH HHS/ -- New York, N.Y. -- Science. 1988 Apr 29;240(4852):640-2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of California, Berkeley 94720.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2834821" target="_blank"〉PubMed〈/a〉
    Keywords: Bacteriophage lambda ; Chemical Phenomena ; Chemistry ; *DNA Damage ; DNA Repair ; DNA, Bacterial/*drug effects ; Escherichia coli/drug effects/*genetics ; Ferrous Compounds ; Free Radicals ; Hydrogen Peroxide/administration & dosage/*pharmacology ; Hydrogen-Ion Concentration ; Hydroxides ; Hydroxyl Radical ; Oxidation-Reduction
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  • 71
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-06-03
    Description: A major portion of the toxicity of hydrogen peroxide in Escherichia coli is attributed to DNA damage mediated by a Fenton reaction that generates active forms of hydroxyl radicals from hydrogen peroxide, DNA-bound iron, and a constant source of reducing equivalents. Kinetic peculiarities of DNA damage production by hydrogen peroxide in vivo can be reproduced by including DNA in an in vitro Fenton reaction system in which iron catalyzes the univalent reduction of hydrogen peroxide by the reduced form of nicotinamide adenine dinucleotide (NADH). To minimize the toxicity of oxygen radicals, the cell utilizes scavengers of these radicals and DNA repair enzymes. On the basis of observations with the model system, it is proposed that the cell may also decrease such toxicity by diminishing available NAD(P)H and by utilizing oxygen itself to scavenge active free radicals into superoxide, which is then destroyed by superoxide dismutase.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Imlay, J A -- Linn, S -- New York, N.Y. -- Science. 1988 Jun 3;240(4857):1302-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉University of California, Berkeley.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3287616" target="_blank"〉PubMed〈/a〉
    Keywords: Chemical Phenomena ; Chemistry ; *DNA Damage ; DNA, Bacterial/*drug effects ; Escherichia coli/drug effects/*genetics ; Free Radicals ; Hydrogen Peroxide/*pharmacology ; Iron ; NAD/metabolism ; Oxidation-Reduction ; Oxygen/*metabolism
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  • 72
    Publication Date: 1988-08-05
    Description: The x-ray structures of the allosteric enzyme aspartate transcarbamylase from Escherichia coli have been solved and refined for both allosteric forms. The T form was determined in the presence of the heterotropic inhibitor cytidine triphosphate, CTP, while the R form was determined in the presence of the bisubstrate analog N-phosphonacetyl-L-aspartate. These two x-ray structures provide the starting point for an understanding of how allosteric enzymes are able to control the rates of metabolic pathways. Insights into the mechanisms of both catalysis and homotropic cooperativity have been obtained by using site-directed mutagenesis to probe residues thought to be critical to the function of the enzyme based on these x-ray structures.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kantrowitz, E R -- Lipscomb, W N -- GM 06920/GM/NIGMS NIH HHS/ -- GM26237/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Aug 5;241(4866):669-74.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Boston College, MA 02167.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3041592" target="_blank"〉PubMed〈/a〉
    Keywords: Allosteric Regulation ; Allosteric Site ; Aspartate Carbamoyltransferase/*physiology ; Binding Sites ; Chemical Phenomena ; Chemistry ; Escherichia coli/*enzymology ; Macromolecular Substances ; Protein Conformation ; Structure-Activity Relationship
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  • 73
    Publication Date: 1988-05-20
    Description: The self-binding properties of a dominant idiotypic antibody (T15) and a minor idiotypic antibody (M603), both specific for phosphorylcholine, were examined as models of self-binding antibodies (autobodies). Observed differences in the self-binding affinity of T15 and M603 relate to variable sequence differences in their respective heavy and light chains. A molecular recognition theory based on the translation of coding and noncoding DNA strands was used to identify complementary amino acid sequences responsible for self-binding. The second hypervariable region of the heavy chain domain, extending into the third framework region, was predicted as the primary self-binding locus. Among peptides synthesized with different variable heavy and light chain regions, a 24-residue peptide spanning the second hypervariable and third framework regions of the heavy chain of T15 was nearly as effective as phosphorycholine in inhibiting the self-binding complexes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kang, C Y -- Brunck, T K -- Kieber-Emmons, T -- Blalock, J E -- Kohler, H -- AG04180/AG/NIA NIH HHS/ -- New York, N.Y. -- Science. 1988 May 20;240(4855):1034-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉IDEC Pharmaceuticals Corporation, La Jolla, CA 92037.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3368787" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Autoantibodies/*immunology ; Choline/pharmacology ; Immunoglobulin Idiotypes/*immunology ; Immunoglobulin Variable Region/*immunology ; Peptides/pharmacology ; Phosphorylcholine/pharmacology ; Protein Binding ; Structure-Activity Relationship
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  • 74
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-07-01
    Description: Synthetic DNA oligomers (tDNAs) corresponding to Escherichia coli tRNA(Phe) or tRNA(Lys) have been synthesized with either deoxythymidine (dT) or deoxyuridine (dU) substituted in the positions occupied by ribouridine or its derivatives. The tDNAs inhibited the aminoacylation of their respective tRNAs with their cognate amino acids, but not the aminoacylation of tRNA(Leu) with Leu. In the presence of aminoacyl-tRNA synthetase, species of both a tDNA(Phe) synthesized with a 3' terminal riboadenosine and a tDNA(Lys) containing only deoxynucleotides could be aminoacylated with the appropriate amino acids, although the Michaelis constant Km and observed maximal rate Vmax values for aminoacylation were increased by three- to fourfold and decreased by two- to threefold, respectively. The aminoacylation of synthetic tDNAs demonstrates that the ribose backbone of a tRNA is not absolutely required for tRNA aminoacylation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Khan, A S -- Roe, B A -- GM-30400/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Jul 1;241(4861):74-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of Oklahoma, Norman 73019.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2455342" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; DNA/genetics/*metabolism ; Deoxyuridine/metabolism ; Dimethyl Sulfoxide/pharmacology ; Escherichia coli/*genetics ; Hydrogen-Ion Concentration ; Kinetics ; Lysine-tRNA Ligase/metabolism ; Molecular Sequence Data ; Phenylalanine-tRNA Ligase/metabolism ; RNA, Bacterial/*genetics ; RNA, Transfer, Amino Acyl/*genetics ; Spermidine/pharmacology ; Structure-Activity Relationship ; Thymidine/metabolism
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  • 75
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-04-01
    Description: The rate of generation of molecular sequence data is forcing the use of computers as a central tool in molecular biology. Current use of computers is limited largely to data management and sequence comparisons, but rapid growth in the volume of data is generating pressure for the development of high-speed analytical methods for deciphering the codes connecting nucleotide sequence with protein structure and function.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉DeLisi, C -- New York, N.Y. -- Science. 1988 Apr 1;240(4848):47-52.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Office of Health and Environmental Research, U.S. Department of Energy, Washington, DC 20545.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3281255" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; *Computers ; DNA/*genetics ; Genetic Diseases, Inborn/genetics ; *Molecular Biology ; Nucleic Acids ; Proteins/genetics/physiology ; Structure-Activity Relationship
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  • 76
    Publication Date: 1988-06-10
    Description: Previous studies involving platelet-derived growth factor (PDGF) have been based on the premise that a single cell-surface receptor binds all three isoforms of PDGF (AA, BB, and AB). It is now shown that two populations of PDGF receptor exist and can be distinguished by their ligand binding specificity. The B receptor binds only the BB dimer, whereas the A/B receptor binds AA, BB, and AB dimers. Human dermal fibroblasts appear to express seven times as much B receptor as A/B receptor. The B receptor is responsible for most PDGF receptor phosphorylation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hart, C E -- Forstrom, J W -- Kelly, J D -- Seifert, R A -- Smith, R A -- Ross, R -- Murray, M J -- Bowen-Pope, D F -- DE07063-11/DE/NIDCR NIH HHS/ -- GM35501/GM/NIGMS NIH HHS/ -- HL18645/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1988 Jun 10;240(4858):1529-31.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pathology, University of Washington, Seattle 98195.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2836952" target="_blank"〉PubMed〈/a〉
    Keywords: Binding, Competitive ; Cell Membrane/metabolism ; Cells, Cultured ; Fibroblasts/metabolism ; Humans ; Kinetics ; Platelet-Derived Growth Factor/*metabolism ; Receptors, Cell Surface/*metabolism ; Receptors, Platelet-Derived Growth Factor ; Skin/*metabolism ; Structure-Activity Relationship
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  • 77
    Publication Date: 1988-11-11
    Description: The crystal structure of a complex containing the DNA-binding domain of lambda repressor and a lambda operator site was determined at 2.5 A resolution and refined to a crystallographic R factor of 24.2 percent. The complex is stabilized by an extensive network of hydrogen bonds between the protein and the sugar-phosphate backbone. Several side chains form hydrogen bonds with sites in the major groove, and hydrophobic contacts also contribute to the specificity of binding. The overall arrangement of the complex is quite similar to that predicted from earlier modeling studies, which fit the protein dimer against linear B-form DNA. However, the cocrystal structure reveals important side chain-side chain interactions that were not predicted from the modeling or from previous genetic and biochemical studies.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jordan, S R -- Pabo, C O -- GM-31471/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Nov 11;242(4880):893-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biophysics, Howard Hughes Medical Institute, 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/3187530" target="_blank"〉PubMed〈/a〉
    Keywords: Base Composition ; Base Sequence ; Binding Sites ; Chemical Phenomena ; Chemistry ; Crystallization ; DNA/*metabolism ; *DNA-Binding Proteins ; Glutamine/metabolism ; Hydrogen Bonding ; Molecular Sequence Data ; Molecular Structure ; Nucleic Acid Conformation ; *Operator Regions, Genetic ; Protein Binding ; Protein Conformation ; Repressor Proteins/genetics/*metabolism ; Sugar Phosphates/metabolism ; Transcription Factors/*metabolism ; Viral Proteins ; Viral Regulatory and Accessory Proteins
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  • 78
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-04-08
    Description: The protein deamidation process involves the conversion of the amide side-chain moieties of asparagine and glutamine residues to carboxyl groups. This conversion is an unusual form of protein modification in that it requires catalysis by an intramolecular reaction where both the substrate (asparagine and glutamine side chains) and "catalytic site" (the peptide nitrogen of the succeeding residue) are constituents of several consecutive residues along the polypeptide chain. The stereochemical factors governing this process were studied with a data base derived from the neutron crystallographic structure of trypsin from which amide groups and oxygen can be unambiguously differentiated because of their different neutron scattering properties. The neutron structure allowed for the direct determination of those residues that were deamidated; 3 of 13 asparagine residues were found to be modified. These modified residues were clearly distinguished by a distinct local conformation and hydrogen-bonding structure in contrast to those observed for the other asparagine residues. No correlation was found between preference to deamidate and the chemical character of residues flanking the site, as had been proposed from previous peptide studies.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kossiakoff, A A -- New York, N.Y. -- Science. 1988 Apr 8;240(4849):191-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pharmaceutical Chemistry, University of California, San Francisco 94143.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3353715" target="_blank"〉PubMed〈/a〉
    Keywords: Amides ; *Asparagine ; Computer Graphics ; *Glutamine ; Hydrogen Bonding ; Models, Molecular ; *Protein Conformation ; Stereoisomerism ; Structure-Activity Relationship ; *Trypsin
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  • 79
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-10-28
    Description: The principle of transition-state stabilization asserts that the occurrence of enzymic catalysis is equivalent to saying that an enzyme binds the transition state much more strongly than it binds the ground-state reactants. An outline of the origin and gradual acceptance of this idea is presented, and elementary transition-state theory is reviewed. It is pointed out that a misconception about the theory has led to oversimplification of the accepted expression relating catalysis and binding, and an amended expression is given. Some implications of the transition-state binding principle are then explored. The amended expression suggests that internal molecular dynamics may also play a role in enzymic catalysis. Although such effects probably do not make a major contribution, their magnitude is completely unknown. Two examples of recent advances due to application of the transition-state binding principle are reviewed, one pertaining to the zinc protease mechanism and the other to the generation of catalytic antibodies.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kraut, J -- New York, N.Y. -- Science. 1988 Oct 28;242(4878):533-40.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉University of California, San Diego, La Jolla 92093.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3051385" target="_blank"〉PubMed〈/a〉
    Keywords: *Catalysis ; Chemistry, Physical ; DNA Mutational Analysis ; Enzymes/*physiology ; Physicochemical Phenomena ; Protein Conformation ; Structure-Activity Relationship
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  • 80
    Publication Date: 1987-01-02
    Description: The alpha-chain of the nicotinic acetylcholine receptor carries the binding sites both for cholinergic ligands and for most experimentally induced or naturally occurring antibodies to the native receptor. By means of expression cloning in Escherichia coli, fusion proteins were derived from specific fragments of a complementary DNA encoding the mouse alpha-chain, allowing the mapping of the toxin-binding site to residues 160-216 and the main immunogenic region to residues 6-85. This approach permits the independent study of different functional domains of a complex receptor molecule and should be generally applicable to other proteins for which complementary DNA clones are available.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Barkas, T -- Mauron, A -- Roth, B -- Alliod, C -- Tzartos, S J -- Ballivet, M -- New York, N.Y. -- Science. 1987 Jan 2;235(4784):77-80.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2432658" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Antibodies, Monoclonal/immunology ; Binding Sites ; Binding, Competitive ; Bungarotoxins/metabolism ; Cloning, Molecular ; Epitopes ; Humans ; Immunosorbent Techniques ; Ligands ; Mice ; Receptors, Nicotinic/genetics/*immunology ; Recombinant Fusion Proteins/immunology ; Species Specificity ; Structure-Activity Relationship
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  • 81
    Publication Date: 1987-01-30
    Description: This and two accompanying reports describe the intrinsic binding energy derived from a single hydrogen bond between an inhibitor and an enzyme. The results were obtained by comparing matched pairs of inhibitors of the zinc endopeptidase thermolysin that bind to the enzyme in an essentially identical manner but differ in the presence or absence of a specific hydrogen bond. This report describes five phosphorus-containing analogs of the peptides carbobenzoxy-Gly-Leu-X, in which the Gly-Leu peptide linkage is replaced with a phosphonate ester (-PO2(-)-O-). Values for the inhibition constants of these inhibitors show a direct relation with those of the corresponding phosphonamidate analogs (-PO2(-)-NH- in place of the Gly-Leu peptide moiety), which have been characterized previously as transition state analogs. However, each phosphonate ester is bound about 840 times more weakly than the analogous phosphonamidate, reflecting the loss of 4.0 +/- 0.1 kilocalories per mole in binding energy. From these results and the crystallographic analysis in the next report, it can be inferred that the value of 4.0 kilocalories per mole represents the intrinsic binding energy arising from a highly specific hydrogen binding interaction.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bartlett, P A -- Marlowe, C K -- CA-22747/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1987 Jan 30;235(4788):569-71.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3810155" target="_blank"〉PubMed〈/a〉
    Keywords: Amides/pharmacology ; Catalysis ; Esters/pharmacology ; Hydrogen Bonding ; Oligopeptides/pharmacology ; Organophosphonates/pharmacology ; Structure-Activity Relationship ; Thermodynamics ; Thermolysin/*antagonists & inhibitors
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  • 82
    Publication Date: 1987-11-20
    Description: Cleavage of the peptide bonds of preprosomatostatin at basic residues near the carboxyl terminus yields somatostatin-14, somatostatin-28, and somatostatin-28 (1-12). However, little is known about the molecular forms derived from the amino terminal portion of the precursor, even though this part of the prohormone is highly conserved through evolution. By using an antibody against the amino terminus of prosomatostatin, a decapeptide with the structure Ala-Pro-Ser-Asp-Pro-Arg-Leu-Arg-Gln-Phe, corresponding to preprosomatostatin (25-34), was isolated from the endocrine portion of the rat stomach, the gastric antrum. The antral decapeptide may represent a bioactive product generated from prosomatostatin after a monobasic cleavage similar to that involved in the formation of somatostatin-28. In fact, a monobasic cleavage requires two basic residues and a domain containing nonpolar amino acids such as alanine or leucine, or both.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Benoit, R -- Ling, N -- Esch, F -- AM I88II/AM/NIADDK NIH HHS/ -- HD 09690/HD/NICHD NIH HHS/ -- New York, N.Y. -- Science. 1987 Nov 20;238(4830):1126-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Montreal General Hospital Research Institute, Department of Medicine, McGill University, Quebec, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2891188" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Hydrolysis ; Immunologic Techniques ; Peptide Fragments/physiology ; Protein Precursors/immunology/*physiology ; Protein Processing, Post-Translational ; Rats ; Somatostatin/immunology/*physiology ; Stomach/*physiology ; Structure-Activity Relationship
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  • 83
    Publication Date: 1987-01-30
    Description: By means of a thermodynamic perturbation method implemented with molecular dynamics, the relative free energy of binding was calculated for the enzyme thermolysin complexed with a pair of phosphonamidate and phosphonate ester inhibitors. The calculated difference in free energy of binding was 4.21 +/- 0.54 kilocalories per mole. This compares well with the experimental value of 4.1 kilocalories per mole. The method is general and can be used to determine a change or "mutation" in any system that can be suitably represented. It is likely to prove useful for protein and drug design.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bash, P A -- Singh, U C -- Brown, F K -- Langridge, R -- Kollman, P A -- GM-29072/GM/NIGMS NIH HHS/ -- RR-1081/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 1987 Jan 30;235(4788):574-6.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3810157" target="_blank"〉PubMed〈/a〉
    Keywords: Amides/pharmacology ; Esters/pharmacology ; Oligopeptides/pharmacology ; Organophosphonates/pharmacology ; Structure-Activity Relationship ; Thermodynamics ; Thermolysin/*antagonists & inhibitors ; X-Ray Diffraction
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  • 84
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1987-03-06
    Description: Ribonuclease mitochondrial RNA processing, a site-specific endoribonuclease involved in primer RNA metabolism in mammalian mitochondria, requires an RNA component for its activity. On the basis of copurification and selective inactivation with complementary oligonucleotides, a 135-nucleotide RNA species, not encoded in the mitochondrial genome, is identified as the RNA moiety of the endoribonuclease. This finding implies transport of a nucleus-encoded RNA, essential for organelle DNA replication, to the mitochondrial matrix.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chang, D D -- Clayton, D A -- GM-33088-16/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1987 Mar 6;235(4793):1178-84.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2434997" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Base Sequence ; Cell Nucleus/*physiology ; Chemical Phenomena ; Chemistry ; Drug Resistance ; Endonucleases/isolation & purification/metabolism ; Enzyme Activation/drug effects ; *Genetic Code ; Humans ; Mammals/*genetics/metabolism ; Micrococcal Nuclease/pharmacology ; Mitochondria/*metabolism ; Oligonucleotides/pharmacology ; Organoids/physiology ; RNA/*biosynthesis/genetics/isolation & purification/physiology ; Ribonucleases/metabolism ; Subcellular Fractions/metabolism
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  • 85
    Publication Date: 1987-01-16
    Description: In the process of protein secretion, amino-terminal signal sequences are key recognition elements; however, the relation between the primary sequence of an amino-terminal peptide and its ability to function as an export signal remains obscure. The limits of variation permitted for functional signal sequences were determined by replacement of the normal signal sequence of Saccharomyces cerevisiae invertase with essentially random peptide sequences. Since about one-fifth of these sequences can function as an export signal the specificity with which signal sequences are recognized must be very low.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kaiser, C A -- Preuss, D -- Grisafi, P -- Botstein, D -- GM18973/GM/NIGMS NIH HHS/ -- GM21253/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1987 Jan 16;235(4786):312-7.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3541205" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Cytoplasm/enzymology ; Extracellular Space/enzymology ; Glycoside Hydrolases/*secretion ; Glycosylation ; Protein Sorting Signals/*physiology ; Saccharomyces cerevisiae/enzymology/metabolism ; Structure-Activity Relationship ; beta-Fructofuranosidase
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  • 86
    Publication Date: 1987-08-14
    Description: Toxic chlorinated dibenzo-p-dioxins are known to be formed in incinerators that burn municipal refuse. These compounds were synthesized by surface-catalyzed reactions on fly ash particulates taken from incinerators. Dioxins were produced catalytically from chlorinated phenol precursors, from non-chlorinated compounds that were chemically dissimilar to dioxins, and from reaction of phenol with inorganic chlorides. The relative amounts of dioxins formed from [13C6]pentachlorophenol with different fly ashes that had been cleaned of all organic compounds corresponded well with those amounts originally found on the samples as received from the incinerators. The optimum temperature range for the formation of dioxins from pentachlorophenol was 250 degrees to 350 degrees C.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Karasek, F W -- Dickson, L C -- New York, N.Y. -- Science. 1987 Aug 14;237(4816):754-6.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3616606" target="_blank"〉PubMed〈/a〉
    Keywords: Chemical Phenomena ; Chemistry ; Dioxins/*chemical synthesis ; Gas Chromatography-Mass Spectrometry ; *Hot Temperature ; Pentachlorophenol ; Polyvinyl Chloride ; *Refuse Disposal ; Tetrachlorodibenzodioxin/analogs & derivatives/*chemical synthesis
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  • 87
    Publication Date: 1987-08-21
    Description: The molecular basis for the marked difference between primate and rodent cells in sensitivity to the cardiac glycoside ouabain has been established by genetic techniques. A complementary DNA encoding the entire alpha 1 subunit of the mouse Na+- and K+-dependent adenosine triphosphatase (ATPase) was inserted into the expression vector pSV2. This engineered DNA molecule confers resistance against 10(-4) M ouabain to monkey CV-1 cells. Deletion of sequences encoding the carboxyl terminus of the alpha 1 subunit abolish the activity of the complementary DNA. The ability to assay the biological activity of this ATPase in a transfection protocol permits the application of molecular genetic techniques to the analysis of structure-function relationships for the enzyme that establishes the internal Na+/K+ environment of most animal cells. The full-length alpha 1 subunit complementary DNA will also be useful as a dominant selectable marker for somatic cell genetic studies utilizing ouabain-sensitive cells.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kent, R B -- Emanuel, J R -- Ben Neriah, Y -- Levenson, R -- Housman, D E -- CA-07919/CA/NCI NIH HHS/ -- CA-26712/CA/NCI NIH HHS/ -- CA-38992/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1987 Aug 21;237(4817):901-3.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3039660" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cells, Cultured ; Cercopithecus aethiops ; DNA/genetics ; Drug Resistance ; Gene Expression Regulation ; Macromolecular Substances ; Mice ; Ouabain/*pharmacology ; Sodium-Potassium-Exchanging ATPase/antagonists & inhibitors/*genetics ; Species Specificity ; Structure-Activity Relationship ; Transfection
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  • 88
    Publication Date: 1987-10-30
    Description: A ring-deleted analog of atrial natriuretic factor--des[Gln18, Ser19, Gly20, Leu21, Gly22] ANF4-23-NH2 (C-ANF4-23)--binds with high affinity to approximately 99% of ANF receptors in the isolated perfused rat kidney. In this preparation, C-ANF4-23 is devoid of detectable renal effects and does not antagonize any of the known renal hemodynamic and natriuretic actions of biologically active ANF1-28. In contrast, both C-ANF4-23 and ANF1-28 increase sodium excretion and decrease blood pressure in intact anesthetized rats. This apparent contradiction is resolved by the finding that the ring-deleted analog markedly increases plasma levels of endogenous immunoreactive ANF in the rat. The results show that the majority of the renal receptors of ANF are biologically silent. This new class of receptors may serve as specific peripheral storage-clearance binding sites, acting as a hormonal buffer system to modulate plasma levels of ANF.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Maack, T -- Suzuki, M -- Almeida, F A -- Nussenzveig, D -- Scarborough, R M -- McEnroe, G A -- Lewicki, J A -- AM-14241/AM/NIADDK NIH HHS/ -- New York, N.Y. -- Science. 1987 Oct 30;238(4827):675-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology, Cornell University Medical College, New York, NY 10021.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2823385" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Atrial Natriuretic Factor/analogs & derivatives/*physiology ; Binding, Competitive ; Cyclic GMP/physiology ; Glomerular Filtration Rate ; Kidney/*physiology ; Kidney Cortex/metabolism ; Kidney Medulla/metabolism ; Natriuresis ; Rats ; Receptors, Atrial Natriuretic Factor ; Receptors, Cell Surface/*physiology ; Structure-Activity Relationship
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  • 89
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1987-08-28
    Description: A monoclonal antibody elicited by a transition-state analog that is representative of an intramolecular six-membered ring cyclization reaction acted as a stereospecific, enzyme-like catalyst for the appropriate substrate. Formation of a single enantiomer of a delta-lactone from the corresponding racemic delta-hydroxyester was accelerated by the antibody by about a factor of 170, which permitted isolation of the lactone in an enantiomeric excess of about 94 percent. This finding demonstrates the feasibility of catalytic-antibody generation for chemical transformations that require stereochemical control.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Napper, A D -- Benkovic, S J -- Tramontano, A -- Lerner, R A -- GM 13306/GM/NIGMS NIH HHS/ -- GM 35318/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1987 Aug 28;237(4818):1041-3.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3616626" target="_blank"〉PubMed〈/a〉
    Keywords: *Antibodies, Monoclonal ; Catalysis ; Chemical Phenomena ; Chemistry ; Cyclization ; *Stereoisomerism
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  • 90
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1987-08-28
    Description: Chemical evidence is needed in both insect endocrinology and sensory physiology to understand hormone and pheromone action at the molecular level. Radiolabeled pheromones and hormones have been synthesized and used to identify binding and catabolic proteins from insect tissues. Chemically modified analogs, including photoaffinity labels and enzyme inhibitors, are among the tools used to covalently modify the specific acceptor or catalytic sites. Such targeted agents can also provide leads for the design of growth and mating disruptants by allowing manipulation of the physiologically important interactions of the chemical signals with macromolecules.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Prestwich, G D -- GM-30899/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1987 Aug 28;237(4818):999-1006.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3616631" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Bees/metabolism ; Chemical Phenomena ; Chemistry ; Cockroaches/metabolism ; Female ; Insect Hormones/*metabolism ; Insects/metabolism ; Juvenile Hormones/metabolism ; Male ; Methoprene/metabolism ; Moths/metabolism ; Pheromones/*metabolism
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  • 91
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1987-03-27
    Description: Many RNAs are complex, globular molecules formed from elements of secondary and tertiary structure analogous to those found in proteins. Little is known about recognition of RNAs by proteins. In the case of transfer RNAs (tRNAs), considerable evidence suggests that elements dispersed in both the one- and three-dimensional structure are important for recognition by aminoacyl tRNA synthetases. Fragments of alanine tRNA synthetase were created by in vitro manipulations of the cloned alaS gene and examined for their interaction with alanine-specific tRNA. Sequences essential for recognition were located near the middle of the polypeptide, juxtaposed to the carboxyl-terminal side of the domain for aminoacyl adenylate synthesis. The most essential part of the tRNA interaction strength and specificity was dependent on a sequence of fewer than 100 amino acids. Within this sequence, and in the context of the proper conformation, a segment of no more than 17 amino acids was responsible for 25% or more of the total synthetase-tRNA free energy of association. The results raise the possibility that an important part of specific RNA recognition by an aminoacyl tRNA synthetase involves a polypeptide segment that is short relative to the total size of the protein.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Regan, L -- Bowie, J -- Schimmel, P -- GM23562/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1987 Mar 27;235(4796):1651-3.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2435005" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphate/metabolism ; Alanine-tRNA Ligase/metabolism ; Amino Acid Sequence ; Amino Acyl-tRNA Synthetases/*metabolism ; Base Sequence ; Cloning, Molecular ; Escherichia coli/enzymology ; RNA/*metabolism ; RNA, Transfer, Amino Acyl/metabolism ; Structure-Activity Relationship ; Substrate Specificity ; Thermodynamics
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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: 1987-10-16
    Description: Chromatographic retention is determined by a relatively small number of amino acids located in a chromatographic contact region on the surface of a polypeptide. This region is determined by the mode of separation and the amino acid distribution within the polypeptide. The contact area may be as small as a few hundred square angstroms in bioaffinity chromatography. In contrast, the contact region in ion exchange, reversed phase, hydrophobic interaction and the other nonbioaffinity separation modes is much broader, ranging from one side to the whole external surface of a polypeptide. Furthermore, structural changes that alter the chromatographic contact region will alter chromatographic properties. Thus, although immunosorbents can be very useful in purifying proteins of similar primary structure, they will be ineffective in discriminating between small, random variations within a structure. Nonbioaffinity columns complement affinity columns in probing a much larger portion of solute surface and being able to discriminate between protein variants.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Regnier, F E -- GM25431/GM/NIGMS NIH HHS/ -- GM33644/GM/NIGMS NIH HHS/ -- GM34759/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1987 Oct 16;238(4825):319-23.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, Purdue University, West Lafayette, IN 47907.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3310233" target="_blank"〉PubMed〈/a〉
    Keywords: Adsorption ; Amino Acids ; Chemical Phenomena ; Chemistry ; *Chromatography ; Chromatography, Affinity ; Chromatography, High Pressure Liquid ; Chromatography, Ion Exchange ; Protein Conformation ; Protein Denaturation ; *Proteins ; Recombinant Proteins ; Surface Properties
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  • 93
    Publication Date: 1987-11-20
    Description: A synthetic 52-residue peptide based on the sequence-specific DNA-binding domain of Hin recombinase (139-190) has been equipped with ethylenediaminetetraacetic acid (EDTA) at the amino terminus. In the presence of Fe(II), this synthetic EDTA-peptide cleaves DNA at Hin recombination sites. The cleavage data reveal that the amino terminus of Hin(139-190) is bound in the minor groove of DNA near the symmetry axis of Hin recombination sites. This work demonstrates the construction of a hybrid peptide combining two functional domains: sequence-specific DNA binding and DNA cleavage.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sluka, J P -- Horvath, S J -- Bruist, M F -- Simon, M I -- Dervan, P B -- GM-09534-02/GM/NIGMS NIH HHS/ -- T32GM07616/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1987 Nov 20;238(4830):1129-32.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3120311" target="_blank"〉PubMed〈/a〉
    Keywords: Bacterial Proteins/*metabolism ; DNA/*metabolism ; DNA Nucleotidyltransferases/*metabolism ; DNA-Binding Proteins/*chemical synthesis ; Edetic Acid ; Ferrous Compounds ; Models, Molecular ; Nucleic Acid Conformation ; Oxidation-Reduction ; Peptide Fragments ; Protein Binding ; Structure-Activity Relationship
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  • 94
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1987-11-20
    Description: The minimum sequence requirements for antigen receptor V-(D)-J joining were studied by constructing recombination-substrates containing synthetic recombination signals and introducing them into a recombination-competent pre-B cell line. Two sets of heptamer (CACTGTG) and nonamer (GGTTTTTGT) sequences were shown to be sufficient to cause the V-(D)-J joining, if the 12- and 23-base pair spacer rule is satisfied. A point mutation in the heptamer sequence, or a change in the combination of the two spacer lengths, drastically reduced the recombination.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Akira, S -- Okazaki, K -- Sakano, H -- AI-18790/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 1987 Nov 20;238(4830):1134-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Microbiology and Immunology, University of California, Berkeley 94720.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3120312" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Base Sequence ; Chromosome Inversion ; *Genes, Immunoglobulin ; Genetic Vectors ; Humans ; Immunoglobulin Variable Region/*genetics ; Immunoglobulin kappa-Chains/genetics ; Mice ; Receptors, Antigen, T-Cell/genetics ; *Recombination, Genetic ; Retroviridae/genetics ; Sequence Homology, Nucleic Acid ; Structure-Activity Relationship
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  • 95
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1987-11-20
    Description: Autoantibodies to aminoacyl-transfer RNA (tRNA) synthetases are common in the human autoimmune diseases polymyositis and dermatomyositis. Sera of the PL-12 specificity contain separate antibodies reacting with alanyl-tRNA synthetase and alanine tRNA (tRNAAla). The antibodies to tRNA recognize at least six distinguishable human tRNAAla species grouped into two sequence families. The antibody-reactive determinants on the tRNA were identified through ribonuclease protection and oligonucleotide binding experiments. The antibody binding site is a seven- to nine-nucleotide sequence containing the anticodon loop and requires an intact anticodon. No requirement for anticodon stem structure or sequence is observed, although the 5' portion of the stem is protected from nuclease attack. Antibodies from several patients appear to share the same specificitym, indicating that the antibodies are induced by a unique sequence feature in the immunogen.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bunn, C C -- Mathews, M B -- New York, N.Y. -- Science. 1987 Nov 20;238(4830):1116-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cold Spring Harbor Laboratory, NY 11724.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2446387" target="_blank"〉PubMed〈/a〉
    Keywords: Alanine-tRNA Ligase/immunology ; Anticodon/*immunology ; Autoantigens/*immunology ; Autoimmune Diseases/*immunology ; Epitopes ; Myositis/*immunology ; Nucleic Acid Conformation ; RNA, Transfer/*immunology ; RNA, Transfer, Ala/*immunology ; RNA, Transfer, Amino Acid-Specific/*immunology ; Structure-Activity Relationship
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  • 96
    Publication Date: 1987-08-21
    Description: The role of the aspartic acid residue in the serine protease catalytic triad Asp, His, and Ser has been tested by replacing Asp102 of trypsin with Asn by site-directed mutagenesis. The naturally occurring and mutant enzymes were produced in a heterologous expression system, purified to homogeneity, and characterized. At neutral pH the mutant enzyme activity with an ester substrate and with the Ser195-specific reagent diisopropylfluorophosphate is approximately 10(4) times less than that of the unmodified enzyme. In contrast to the dramatic loss in reactivity of Ser195, the mutant trypsin reacts with the His57-specific reagent, tosyl-L-lysine chloromethylketone, only five times less efficiently than the unmodified enzyme. Thus, the ability of His57 to react with this affinity label is not severely compromised. The catalytic activity of the mutant enzyme increases with increasing pH so that at pH 10.2 the kcat is 6 percent that of trypsin. Kinetic analysis of this novel activity suggests this is due in part to participation of either a titratable base or of hydroxide ion in the catalytic mechanism. By demonstrating the importance of the aspartate residue in catalysis, especially at physiological pH, these experiments provide a rationalization for the evolutionary conservation of the catalytic triad.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Craik, C S -- Roczniak, S -- Largman, C -- Rutter, W J -- GM 10765/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1987 Aug 21;237(4817):909-13.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3303334" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Asparagine ; *Aspartic Acid ; Binding Sites ; Catalysis ; *Endopeptidases ; Hydrogen-Ion Concentration ; Kinetics ; Rats ; Serine Endopeptidases ; Structure-Activity Relationship ; Substrate Specificity
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  • 97
    Publication Date: 1987-05-01
    Description: Neoplastic transformation has been associated with a variety of structural changes in cell surface carbohydrates, most notably increased sialylation and beta 1-6-linked branching of complex-type asparagine (Asn)-linked oligosaccharides (that is, -GlcNAc beta 1-6Man alpha 1-6Man beta 1-). However, little is known about the relevant glycoproteins or how these transformation-related changes in oligosaccharide biosynthesis may affect the malignant phenotype. Here it is reported that a cell surface glycoprotein, gp 130, is a major target of increased beta 1-6-linked branching and that the expression of these oligosaccharide structures is directly related to the metastatic potential of the cells. Glycosylation mutants of a metastatic tumor cell line were selected that are deficient in both beta 1-6 GlcNAc transferase V activity and metastatic potential in situ. Moreover, induction of increased beta 1-6 branching in clones of a nonmetastatic murine mammary carcinoma correlated strongly with acquisition of metastatic potential. The results indicate that increased beta 1-6-linked branching of complex-type oligosaccharides on gp 130 may be an important feature of tumor progression related to increased metastatic potential.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Dennis, J W -- Laferte, S -- Waghorne, C -- Breitman, M L -- Kerbel, R S -- R0I-CA41233/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1987 May 1;236(4801):582-5.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2953071" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Asparagine ; Carbohydrate Conformation ; Cell Line ; Cell Transformation, Neoplastic ; Glucosyltransferases/metabolism ; Glycosylation ; Lysosome-Associated Membrane Glycoproteins ; *Membrane Glycoproteins ; Membrane Proteins/metabolism ; Mice ; Mutation ; *N-Acetylglucosaminyltransferases ; *Neoplasm Metastasis ; Neoplasms, Experimental/genetics/metabolism ; *Oligosaccharides/biosynthesis ; Structure-Activity Relationship
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  • 98
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1987-09-25
    Description: The aspartate receptor of Escherichia coli and Salmonella typhimurium is a cell surface sensory transducer that binds extracellular aspartate and sends a transmembrane signal to the inside of the bacterium. The flexibility and allostery of this receptor was examined by placing sulfhydryl groups as potential cross-linking sites at targeted locations in the protein. Seven different mutant receptors were constructed, each containing a single cysteine residue at a different position in the primary structure. Intramolecular disulfide bond formation within oligomers of these mutant receptors is shown to trap structural fluctuations and to detect ligand-induced changes in structure. The results indicate that the receptor oligomer has a flexible, dynamic structure which undergoes a global change upon aspartate binding.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Falke, J J -- Koshland, D E Jr -- New York, N.Y. -- Science. 1987 Sep 25;237(4822):1596-600.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2820061" target="_blank"〉PubMed〈/a〉
    Keywords: Allosteric Regulation ; Bacterial Proteins/*physiology ; *Chemotaxis ; Cloning, Molecular ; Cysteine ; Disulfides ; Macromolecular Substances ; Membrane Proteins/*physiology ; Mutation ; Protein Conformation ; *Receptors, Amino Acid ; Receptors, Neurotransmitter/*physiology ; Structure-Activity Relationship
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  • 99
    Publication Date: 1987-04-24
    Description: Transcriptional enhancement is a general mechanism for regulation of gene expression in which particular proteins bound to specific DNA sequences stimulate the efficiency of initiation from linked promoters. One such protein, the glucocorticoid receptor, mediates enhancement in a glucocorticoid hormone-dependent manner. In this study, a region of the 795-amino acid rat glucocorticoid receptor that is active in transcriptional enhancement was identified. The active region was defined by expressing various receptor deletion mutants in stably and transiently transfected cells and examining the regulated transcription of hormone-responsive genes. Mutant receptors lacking as many as 439 amino-terminal amino acids retained activity, as did those with as many as 270 carboxyl-terminal amino acids deleted. This suggests that the 86-amino acid segment between the most extensive terminal deletions, which also includes sequences required for specific DNA binding in vitro, is sufficient for enhancer activation. In fact, a 150-amino acid receptor fragment that encompasses this segment mediates constitutive enhancement.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Miesfeld, R -- Godowski, P J -- Maler, B A -- Yamamoto, K R -- New York, N.Y. -- Science. 1987 Apr 24;236(4800):423-7.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3563519" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; DNA-Binding Proteins/*genetics ; *Enhancer Elements, Genetic ; *Genes, Regulator ; Mutation ; Rats ; Receptors, Glucocorticoid/*genetics ; Structure-Activity Relationship ; Transfection
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  • 100
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1987-03-06
    Description: Phosphate esters and anhydrides dominate the living world but are seldom used as intermediates by organic chemists. Phosphoric acid is specially adapted for its role in nucleic acids because it can link two nucleotides and still ionize; the resulting negative charge serves both to stabilize the diesters against hydrolysis and to retain the molecules within a lipid membrane. A similar explanation for stability and retention also holds for phosphates that are intermediary metabolites and for phosphates that serve as energy sources. Phosphates with multiple negative charges can react by way of the monomeric metaphosphate ion PO3- as an intermediate. No other residue appears to fulfill the multiple roles of phosphate in biochemistry. Stable, negatively charged phosphates react under catalysis by enzymes; organic chemists, who can only rarely use enzymatic catalysis for their reactions, need more highly reactive intermediates than phosphates.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Westheimer, F H -- New York, N.Y. -- Science. 1987 Mar 6;235(4793):1173-8.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2434996" target="_blank"〉PubMed〈/a〉
    Keywords: Amides ; Animals ; Arsenates ; Chemical Phenomena ; Chemistry ; Citrates ; Citric Acid ; Electrochemistry ; Humans ; Hydrolysis ; Ions ; Nucleic Acids/metabolism ; Phosphates/metabolism/*physiology ; RNA/metabolism ; Silicic Acid
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