View source for 2pyi

==Crystal structure of Glycogen Phosphorylase in complex with glucosyl triazoleacetamide==
<StructureSection load='2pyi' size='340' side='right' caption='[[2pyi]], [[Resolution|resolution]] 1.88&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2pyi]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Oryctolagus_cuniculus Oryctolagus cuniculus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2PYI OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2PYI FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=DL8:N-[(4-PHENYL-1H-1,2,3-TRIAZOL-1-YL)ACETYL]-BETA-D-GLUCOPYRANOSYLAMINE'>DL8</scene>, <scene name='pdbligand=DMS:DIMETHYL+SULFOXIDE'>DMS</scene></td></tr>
<tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=LLP:2-LYSINE(3-HYDROXY-2-METHYL-5-PHOSPHONOOXYMETHYL-PYRIDIN-4-YLMETHANE)'>LLP</scene></td></tr>
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[2pyd|2pyd]]</td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Phosphorylase Phosphorylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.1 2.4.1.1] </span></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2pyi FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2pyi OCA], [http://pdbe.org/2pyi PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=2pyi RCSB], [http://www.ebi.ac.uk/pdbsum/2pyi PDBsum]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/PYGM_RABIT PYGM_RABIT]] Phosphorylase is an important allosteric enzyme in carbohydrate metabolism. Enzymes from different sources differ in their regulatory mechanisms and in their natural substrates. However, all known phosphorylases share catalytic and structural properties. 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/py/2pyi_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/chain_selection.php?pdb_ID=2ata ConSurf].
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== Publication Abstract from PubMed ==
4-Phenyl-N-(beta-D-glucopyranosyl)-1H-1,2,3-triazole-1-acetamide (glucosyltriazolylacetamide) has been studied in kinetic and crystallographic experiments with glycogen phosphorylase b (GPb), in an effort to utilize its potential as a lead for the design of potent antihyperglycaemic agents. Docking and molecular dynamics (MD) calculations have been used to monitor more closely the binding modes in operation and compare the results with experiment. Kinetic experiments in the direction of glycogen synthesis showed that glucosyltriazolylacetamide is a better inhibitor (K(i) = 0.18 mM) than the parent compound alpha-D-glucose (K(i) = 1.7 mM) or beta-D-glucose (K(i) = 7.4 mM) but less potent inhibitor than the lead compound N-acetyl-beta-D-glucopyranosylamine (K(i) = 32 muM). To elucidate the molecular basis underlying the inhibition of the newly identified compound, we determined the structure of GPb in complex with glucosyltriazolylacetamide at 100 K to 1.88 A resolution, and the structure of the compound in the free form. Glucosyltriazolylacetamide is accommodated in the catalytic site of the enzyme and the glucopyranose interacts in a manner similar to that observed in the GPb-alpha-D-glucose complex, while the substituent group in the beta-position of the C1 atom makes additional hydrogen bonding and van der Waals interactions to the protein. A bifurcated donor type hydrogen bonding involving O3H, N3, and N4 is seen as an important structural motif strengthening the binding of glucosyltriazolylacetamide with GP which necessitated change in the torsion about C8--N2 bond by about 62 degrees going from its free to the complex form with GPb. On binding to GP, glucosyltriazolylacetamide induces significant conformational changes in the vicinity of this site. Specifically, the 280s loop (residues 282-288) shifts 0.7 to 3.1 A (CA atoms) to accommodate glucosyltriazolylacetamide. These conformational changes do not lead to increased contacts between the inhibitor and the protein that would improve ligand binding compared with the lead compound. In the molecular modeling calculations, the GOLD docking runs with and without the crystallographic ordered cavity waters using the GoldScore scoring function, and without cavity waters using the ChemScore scoring function successfully reproduced the crystallographic binding conformation. However, the GLIDE docking calculations both with (GLIDE XP) and without (GLIDE SP and XP) the cavity water molecules were, impressively, further able to accurately reproduce the finer details of the GPb-glucosyltriazolylacetamide complex structure. The importance of cavity waters in flexible receptor MD calculations compared to "rigid" (docking) is analyzed and highlighted, while in the MD itself very little conformational flexibility of the glucosyltriazolylacetamide ligand was observed over the time scale of the simulations. Proteins 2007. (c) 2007 Wiley-Liss, Inc.

Crystallographic and computational studies on 4-phenyl-N-(beta-D-glucopyranosyl)-1H-1,2,3-triazole-1-acetamide, an inhibitor of glycogen phosphorylase: Comparison with alpha-D-glucose, N-acetyl-beta-D-glucopyranosylamine and N-benzoyl-N'-beta-D-glucopyranosyl urea binding.,Alexacou KM, Hayes JM, Tiraidis C, Zographos SE, Leonidas DD, Chrysina ED, Archontis G, Oikonomakos NG, Paul JV, Varghese B, Loganathan D Proteins. 2007 Nov 27;. PMID:18041758<ref>PMID:18041758</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 2pyi" style="background-color:#fffaf0;"></div>

==See Also==
*[[Glycogen Phosphorylase|Glycogen Phosphorylase]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Oryctolagus cuniculus]]
[[Category: Phosphorylase]]
[[Category: Alexacou, K M]]
[[Category: Chrysina, E D]]
[[Category: Hayes, J]]
[[Category: Oikonomakos, N G]]
[[Category: Tiraidis, C]]
[[Category: Zographos, S E]]
[[Category: Glycogenolysis]]
[[Category: Inhibition]]
[[Category: Transferase]]
[[Category: Type 2 diabetes]]