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| [[Image:2pwe.gif|left|200px]]<br /><applet load="2pwe" size="350" color="white" frame="true" align="right" spinBox="true"
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| caption="2pwe, resolution 2.0Å" />
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| '''Crystal structure of the MutB E254Q mutant in complex with the substrate sucrose'''<br />
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| ==Overview== | | ==Crystal structure of the MutB E254Q mutant in complex with the substrate sucrose== |
| Various diseases related to the overconsumption of sugar make a growing need for sugar substitutes. Because sucrose is an inexpensive and readily available d-glucose donor, the industrial potential for enzymatic synthesis of the sucrose isomers trehalulose and/or isomaltulose from sucrose is large. The product specificity of sucrose isomerases that catalyze this reaction depends essentially on the possibility for tautomerization of sucrose, which is required for trehalulose formation. For optimal use of the enzyme, targeting controlled synthesis of these functional isomers, it is necessary to minimize the side reactions. This requires an extensive analysis of substrate binding modes and of the specificity-determining sites in the structure. The 1.6-2.2-A resolution three-dimensional structures of native and mutant complexes of a trehalulose synthase from Pseudomonas mesoacidophila MX-45 mimic successive states of the enzyme reaction. Combined with mutagenesis studies they give for the first time thorough insights into substrate recognition and processing and reaction specificities of these enzymes. Among the important outcomes of this study is the revelation of an aromatic clamp defined by Phe(256) and Phe(280) playing an essential role in substrate recognition and in controlling the reaction specificity, which is further supported by mutagenesis studies. Furthermore, this study highlights essential residues for binding the glucosyl and fructosyl moieties. The introduction of subtle changes informed by comparative three-dimensional structural data observed within our study can lead to fundamental modifications in the mode of action of sucrose isomerases and hence provide a template for industrial catalysts.
| | <StructureSection load='2pwe' size='340' side='right'caption='[[2pwe]], [[Resolution|resolution]] 2.00Å' scene=''> |
| | == Structural highlights == |
| | <table><tr><td colspan='2'>[[2pwe]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Burkholderia_ubonensis_subsp._mesacidophila Burkholderia ubonensis subsp. mesacidophila]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2PWE OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2PWE 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]] 2Å</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>, <scene name='pdbligand=FRU:FRUCTOSE'>FRU</scene>, <scene name='pdbligand=GLC:ALPHA-D-GLUCOSE'>GLC</scene>, <scene name='pdbligand=PRD_900003:sucrose'>PRD_900003</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=2pwe FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2pwe OCA], [https://pdbe.org/2pwe PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2pwe RCSB], [https://www.ebi.ac.uk/pdbsum/2pwe PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2pwe ProSAT]</span></td></tr> |
| | </table> |
| | == Function == |
| | [https://www.uniprot.org/uniprot/Q2PS28_9BURK Q2PS28_9BURK] |
| | == 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/pw/2pwe_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=2pwe ConSurf]. |
| | <div style="clear:both"></div> |
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| ==About this Structure== | | ==See Also== |
| 2PWE is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_mesoacidophila Pseudomonas mesoacidophila] with <scene name='pdbligand=SUC:'>SUC</scene> and <scene name='pdbligand=CA:'>CA</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Isomaltulose_synthase Isomaltulose synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.4.99.11 5.4.99.11] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2PWE OCA].
| | *[[Trehalulose synthase|Trehalulose synthase]] |
| | | __TOC__ |
| ==Reference==
| | </StructureSection> |
| Trehalulose synthase native and carbohydrate complexed structures provide insights into sucrose isomerization., Ravaud S, Robert X, Watzlawick H, Haser R, Mattes R, Aghajari N, J Biol Chem. 2007 Sep 21;282(38):28126-36. Epub 2007 Jun 27. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=17597061 17597061]
| | [[Category: Burkholderia ubonensis subsp. mesacidophila]] |
| [[Category: Isomaltulose synthase]] | | [[Category: Large Structures]] |
| [[Category: Pseudomonas mesoacidophila]]
| | [[Category: Aghajari N]] |
| [[Category: Single protein]] | | [[Category: Haser R]] |
| [[Category: Aghajari, N.]] | | [[Category: Ravaud S]] |
| [[Category: Haser, R.]] | | [[Category: Robert X]] |
| [[Category: Ravaud, S.]] | |
| [[Category: Robert, X.]] | |
| [[Category: CA]]
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| [[Category: SUC]]
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| [[Category: (beta/alpha)8]]
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| [[Category: alpha-amylase family]]
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| [[Category: barrel]]
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| [[Category: enzyme-substrate complex]]
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| [[Category: sucrose isomerase]]
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| [[Category: trehalulose synthase]]
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| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 18:33:46 2008''
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