View source for 1qm5


==Phosphorylase recognition and phosphorylysis of its oligosaccharide substrate: answers to a long outstanding question==
<StructureSection load='1qm5' size='340' side='right'caption='[[1qm5]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1qm5]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QM5 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1QM5 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GLC:ALPHA-D-GLUCOSE'>GLC</scene>, <scene name='pdbligand=PLP:PYRIDOXAL-5-PHOSPHATE'>PLP</scene>, <scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</scene>, <scene name='pdbligand=SGC:4-DEOXY-4-THIO-BETA-D-GLUCOPYRANOSE'>SGC</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1qm5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1qm5 OCA], [https://pdbe.org/1qm5 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1qm5 RCSB], [https://www.ebi.ac.uk/pdbsum/1qm5 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1qm5 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/PHSM_ECOLI PHSM_ECOLI] 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/qm/1qm5_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/main_output.php?pdb_ID=1qm5 ConSurf].
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== Publication Abstract from PubMed ==
Phosphorylases are key enzymes of carbohydrate metabolism. Structural studies have provided explanations for almost all features of control and substrate recognition of phosphorylase but one question remains unanswered. How does phosphorylase recognize and cleave an oligosaccharide substrate? To answer this question we turned to the Escherichia coli maltodextrin phosphorylase (MalP), a non-regulatory phosphorylase that shares similar kinetic and catalytic properties with the mammalian glycogen phosphorylase. The crystal structures of three MalP-oligosaccharide complexes are reported: the binary complex of MalP with the natural substrate, maltopentaose (G5); the binary complex with the thio-oligosaccharide, 4-S-alpha-D-glucopyranosyl-4-thiomaltotetraose (GSG4), both at 2.9 A resolution; and the 2.1 A resolution ternary complex of MalP with thio-oligosaccharide and phosphate (GSG4-P). The results show a pentasaccharide bound across the catalytic site of MalP with sugars occupying sub-sites -1 to +4. Binding of GSG4 is identical to the natural pentasaccharide, indicating that the inactive thio compound is a close mimic of the natural substrate. The ternary MalP-GSG4-P complex shows the phosphate group poised to attack the glycosidic bond and promote phosphorolysis. In all three complexes the pentasaccharide exhibits an altered conformation across sub-sites -1 and +1, the site of catalysis, from the preferred conformation for alpha(1-4)-linked glucosyl polymers.

Phosphorylase recognition and phosphorolysis of its oligosaccharide substrate: answers to a long outstanding question.,Watson KA, McCleverty C, Geremia S, Cottaz S, Driguez H, Johnson LN EMBO J. 1999 Sep 1;18(17):4619-32. PMID:10469642<ref>PMID:10469642</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 1qm5" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Cottaz S]]
[[Category: Driguez H]]
[[Category: Geremia S]]
[[Category: Johnson LN]]
[[Category: McCleverty C]]
[[Category: Watson KA]]