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| [[Image:1e7m.gif|left|200px]]<br />
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| <applet load="1e7m" size="450" color="white" frame="true" align="right" spinBox="true"
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| caption="1e7m, resolution 2.54Å" />
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| '''ACTIVE SITE MUTANT (D177->N) OF GLUCOSE 6-PHOSPHATE DEHYDROGENASE FROM LEUCONOSTOC MESENTEROIDES'''<br />
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| ==Overview== | | ==ACTIVE SITE MUTANT (D177->N) OF GLUCOSE 6-PHOSPHATE DEHYDROGENASE FROM LEUCONOSTOC MESENTEROIDES== |
| The role of Asp-177 in the His-Asp catalytic dyad of glucose 6-phosphate, dehydrogenase from Leuconostoc mesenteroides has been investigated by a, structural and functional characterization of the D177N mutant enzyme. Its, three-dimensional structure has been determined by X-ray, cryocrystallography in the presence of NAD(+) and in the presence of, glucose 6-phosphate plus NADPH. The structure of a glucose 6-phosphate, complex of a mutant (Q365C) with normal enzyme activity has also been, determined and substrate binding compared. To understand the effect of, Asp-177 on the ionization properties of the catalytic base His-240, the pH, dependence of kinetic parameters has been determined for the D177N mutant, and compared to that of the wild-type enzyme. The structures give details, of glucose 6-phosphate binding and show that replacement of the Asp-177 of, the catalytic dyad with asparagine does not affect the overall structure, of glucose 6-phosphate dehydrogenase. Additionally, the evidence suggests, that the productive tautomer of His-240 in the D177N mutant enzyme is, stabilized by a hydrogen bond with Asn-177; hence, the mutation does not, affect tautomer stabilization. We conclude, therefore, that the absence of, a negatively charged aspartate at 177 accounts for the decrease in, catalytic activity at pH 7.8. Structural analysis suggests that the pH, dependence of the kinetic parameters of D177N glucose 6-phosphate, dehydrogenase results from an ionized water molecule replacing the missing, negative charge of the mutated Asp-177 at high pH. Glucose 6-phosphate, binding orders and orients His-178 in the D177N-glucose 6-phosphate-NADPH, ternary complex and appears to be necessary to form this water-binding, site.
| | <StructureSection load='1e7m' size='340' side='right'caption='[[1e7m]], [[Resolution|resolution]] 2.54Å' scene=''> |
| | == Structural highlights == |
| | <table><tr><td colspan='2'>[[1e7m]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Leuconostoc_mesenteroides Leuconostoc mesenteroides]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1E7M OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1E7M 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]] 2.54Å</td></tr> |
| | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</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=1e7m FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1e7m OCA], [https://pdbe.org/1e7m PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1e7m RCSB], [https://www.ebi.ac.uk/pdbsum/1e7m PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1e7m ProSAT]</span></td></tr> |
| | </table> |
| | == Function == |
| | [https://www.uniprot.org/uniprot/G6PD_LEUME G6PD_LEUME] |
| | == 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/e7/1e7m_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=1e7m ConSurf]. |
| | <div style="clear:both"></div> |
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| ==About this Structure== | | ==See Also== |
| 1E7M is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Leuconostoc_mesenteroides Leuconostoc mesenteroides] with CA as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Glucose-6-phosphate_1-dehydrogenase Glucose-6-phosphate 1-dehydrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.1.1.49 1.1.1.49] Structure known Active Site: CA1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1E7M OCA].
| | *[[Glucose 6-phosphate dehydrogenase|Glucose 6-phosphate dehydrogenase]] |
| | | __TOC__ |
| ==Reference==
| | </StructureSection> |
| An examination of the role of asp-177 in the His-Asp catalytic dyad of Leuconostoc mesenteroides glucose 6-phosphate dehydrogenase: X-ray structure and pH dependence of kinetic parameters of the D177N mutant enzyme., Cosgrove MS, Gover S, Naylor CE, Vandeputte-Rutten L, Adams MJ, Levy HR, Biochemistry. 2000 Dec 12;39(49):15002-11. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=11106478 11106478]
| | [[Category: Large Structures]] |
| [[Category: Glucose-6-phosphate 1-dehydrogenase]] | |
| [[Category: Leuconostoc mesenteroides]] | | [[Category: Leuconostoc mesenteroides]] |
| [[Category: Single protein]]
| | [[Category: Adams MJ]] |
| [[Category: Adams, M.J.]] | | [[Category: Cosgrove MS]] |
| [[Category: Cosgrove, M.S.]] | | [[Category: Gover S]] |
| [[Category: Gover, S.]] | |
| [[Category: CA]]
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| [[Category: glucose metabolism]]
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| [[Category: oxidoreductase (choh(d) - nad(p))]]
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| ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 16:07:29 2007''
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