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  • 1
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    Domain separation in the activation of glycogen phosphorylase a (1989)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1989-08-04
    Description: The crystal structure of glycogen phosphorylase a complexed with its substrates, orthophosphate and maltopentaose, has been determined and refined at a resolution of 2.8 angstroms. With oligosaccaride bound at the glycogen storage site, the phosphate ion binds at the catalytic site and causes the regulatory and catalytic domains to separate with the loss of stabilizing interactions between them. Homotropic cooperativity between the active sites of the allosteric dimer results from rearrangements in isologous contacts between symmetry-related helices in the subunit interface. The conformational changes in the core of the interface are correlated with those observed on covalent activation by phosphorylation at Ser14 (phosphorylase b----a).〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Goldsmith, E J -- Sprang, S R -- Hamlin, R -- Xuong, N H -- Fletterick, R J -- DK31507-05/DK/NIDDK NIH HHS/ -- GM00085-05/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1989 Aug 4;245(4917):528-32.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas 75235.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2756432" target="_blank"〉PubMed〈/a〉
    Keywords: Allosteric Site ; Amino Acid Sequence ; Binding Sites ; Catalysis ; Crystallization ; Crystallography ; Enzyme Activation ; Glucosephosphates/metabolism ; Glycogen/metabolism ; Macromolecular Substances ; Molecular Sequence Data ; Molecular Structure ; Oligosaccharides ; Phosphates/metabolism ; Phosphorylase a/*metabolism ; Phosphorylases/*metabolism ; Protein Conformation ; X-Ray Diffraction
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 2
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    A protein phosphorylation switch at the conserved allosteric site in GP (1996)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1996-09-13
    Description: A phosphorylation-initiated mechanism of local protein refolding activates yeast glycogen phosphorylase (GP). Refolding of the phosphorylated amino-terminus was shown to create a hydrophobic cluster that wedges into the subunit interface of the enzyme to trigger activation. The phosphorylated threonine is buried in the allosteric site. The mechanism implicates glucose 6-phosphate, the allosteric inhibitor, in facilitating dephosphorylation by dislodging the buried covalent phosphate through binding competition. Thus, protein phosphorylation-dephosphorylation may also be controlled through regulation of the accessibility of the phosphorylation site to kinases and phosphatases. In mammalian glycogen phosphorylase, phosphorylation occurs at a distinct locus. The corresponding allosteric site binds a ligand activator, adenosine monophosphate, which triggers activation by a mechanism analogous to that of phosphorylation in the yeast enzyme.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lin, K -- Rath, V L -- Dai, S C -- Fletterick, R J -- Hwang, P K -- DK32822/DK/NIDDK NIH HHS/ -- New York, N.Y. -- Science. 1996 Sep 13;273(5281):1539-42.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Biophysics, University of California at San Francisco, 513 Parnassus, San Francisco, CA 94143, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8703213" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Monophosphate/metabolism ; Allosteric Site ; Amino Acid Sequence ; Animals ; Crystallography, X-Ray ; Enzyme Activation ; Enzyme Inhibitors/metabolism/pharmacology ; Glucose-6-Phosphate ; Glucosephosphates/metabolism/pharmacology ; Models, Molecular ; Molecular Sequence Data ; Phosphorylases/antagonists & inhibitors/*chemistry/*metabolism ; Phosphorylation ; *Protein Conformation ; Protein Folding ; Protein Structure, Secondary ; Saccharomyces cerevisiae/enzymology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 3
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    Crystal structure of a catalytic antibody with a serine protease active site (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1994-08-19
    Description: The three-dimensional structure of an unusually active hydrolytic antibody with a phosphonate transition state analog (hapten) bound to the active site has been solved to 2.5 A resolution. The antibody (17E8) catalyzes the hydrolysis of norleucine and methionine phenyl esters and is selective for amino acid esters that have the natural alpha-carbon L configuration. A plot of the pH-dependence of the antibody-catalyzed reaction is bell-shaped with an activity maximum at pH 9.5; experiments on mechanism lend support to the formation of a covalent acyl-antibody intermediate. The structural and kinetic data are complementary and support a hydrolytic mechanism for the antibody that is remarkably similar to that of the serine proteases. The antibody active site contains a Ser-His dyad structure proximal to the phosphorous atom of the bound hapten that resembles two of the three components of the Ser-His-Asp catalytic triad of serine proteases. The antibody active site also contains a Lys residue to stabilize oxyanion formation, and a hydrophobic binding pocket for specific substrate recognition of norleucine and methionine side chains. The structure identifies active site residues that mediate catalysis and suggests specific mutations that may improve the catalytic efficiency of the antibody. This high resolution structure of a catalytic antibody-hapten complex shows that antibodies can converge on active site structures that have arisen through natural enzyme evolution.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zhou, G W -- Guo, J -- Huang, W -- Fletterick, R J -- Scanlan, T S -- DK39304/DK/NIDDK NIH HHS/ -- New York, N.Y. -- Science. 1994 Aug 19;265(5175):1059-64.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Biophysics, University of California, San Francisco 94143-0448.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8066444" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Antibodies, Catalytic/*chemistry/immunology/metabolism ; Binding Sites ; Computer Graphics ; Crystallization ; Crystallography, X-Ray ; Haptens/metabolism ; Hydrogen Bonding ; Hydrogen-Ion Concentration ; Hydrolysis ; Models, Molecular ; Molecular Sequence Data ; Protein Conformation ; Serine Endopeptidases/*chemistry/metabolism
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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