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| [[Image:1xym.gif|left|200px]]
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| {{Structure
| | ==THE ROLE OF THE DIVALENT METAL ION IN SUGAR BINDING, RING OPENING, AND ISOMERIZATION BY D-XYLOSE ISOMERASE: REPLACEMENT OF A CATALYTIC METAL BY AN AMINO-ACID== |
| |PDB= 1xym |SIZE=350|CAPTION= <scene name='initialview01'>1xym</scene>, resolution 1.8Å
| | <StructureSection load='1xym' size='340' side='right'caption='[[1xym]], [[Resolution|resolution]] 1.80Å' scene=''> |
| |SITE= | | == Structural highlights == |
| |LIGAND= <scene name='pdbligand=GLO:D-GLUCOSE+IN+LINEAR+FORM'>GLO</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=OH:HYDROXIDE+ION'>OH</scene>
| | <table><tr><td colspan='2'>[[1xym]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Streptomyces_olivochromogenes Streptomyces olivochromogenes]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XYM OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1XYM FirstGlance]. <br> |
| |ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Xylose_isomerase Xylose isomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.3.1.5 5.3.1.5] </span>
| | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.8Å</td></tr> |
| |GENE=
| | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GLO:D-GLUCOSE+IN+LINEAR+FORM'>GLO</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=OH:HYDROXIDE+ION'>OH</scene></td></tr> |
| |DOMAIN=
| | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1xym FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1xym OCA], [https://pdbe.org/1xym PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1xym RCSB], [https://www.ebi.ac.uk/pdbsum/1xym PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1xym ProSAT]</span></td></tr> |
| |RELATEDENTRY=
| | </table> |
| |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1xym FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1xym OCA], [http://www.ebi.ac.uk/pdbsum/1xym PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1xym RCSB]</span>
| | == Function == |
| }}
| | [https://www.uniprot.org/uniprot/XYLA_STROL XYLA_STROL] Involved in D-xylose catabolism. |
| | == 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/xy/1xym_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=1xym ConSurf]. |
| | <div style="clear:both"></div> |
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| '''THE ROLE OF THE DIVALENT METAL ION IN SUGAR BINDING, RING OPENING, AND ISOMERIZATION BY D-XYLOSE ISOMERASE: REPLACEMENT OF A CATALYTIC METAL BY AN AMINO-ACID'''
| | ==See Also== |
| | | *[[D-xylose isomerase 3D structures|D-xylose isomerase 3D structures]] |
| | | __TOC__ |
| ==Overview== | | </StructureSection> |
| The distinct roles of the two magnesium ions essential to the activity of D-xylose isomerase from Streptomyces olivochromogenes were examined. The enzyme-magnesium complex was isolated, and the stoichiometry of cation binding determined by neutron activation analysis to be 2 mol of magnesium per mole of enzyme. A plot of Mg2+ added versus Mg2+ bound to enzyme is consistent with apparent KD values of < or = 0.5-1.0 mM for one Mg2+ and < or = 2-5 mM for the second. A site-directed mutant of D-xylose isomerase was designed to remove the tighter, tetracoordinated magnesium binding site (site 1, Mg-1); Glu180 was replaced with Lys180. The stoichiometry of metal binding to this mutant, E180K, is 1 mol of magnesium per mole of enzyme. Ring-opening assays with 1-thioglucose (H2S released upon ring opening) show E180K catalyzes the opening of the sugar ring at 20% the rate of the wild-type, but E180K does not catalyze isomerization of glucose to fructose. Thus, the magnesium bound to Glu180 is essential for isomerization but not essential for ring opening. The X-ray crystallographic structures of E180K in the absence of magnesium and in the presence and absence of 250 mM glucose were obtained to 1.8-A resolution and refined to R factors of 17.7% and 19.7%, respectively. The wild-type and both E180K structures show no significant structural differences, except the epsilon-amino group of Lys180, which occupies the position usually occupied by the Mg-1.(ABSTRACT TRUNCATED AT 250 WORDS)
| | [[Category: Large Structures]] |
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| ==About this Structure==
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| 1XYM is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Streptomyces_olivochromogenes Streptomyces olivochromogenes]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XYM OCA].
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| ==Reference==
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| Role of the divalent metal ion in sugar binding, ring opening, and isomerization by D-xylose isomerase: replacement of a catalytic metal by an amino acid., Allen KN, Lavie A, Glasfeld A, Tanada TN, Gerrity DP, Carlson SC, Farber GK, Petsko GA, Ringe D, Biochemistry. 1994 Feb 15;33(6):1488-94. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/7906142 7906142]
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| [[Category: Single protein]] | |
| [[Category: Streptomyces olivochromogenes]] | | [[Category: Streptomyces olivochromogenes]] |
| [[Category: Xylose isomerase]]
| | [[Category: Allen KN]] |
| [[Category: Allen, K N.]] | | [[Category: Lavie A]] |
| [[Category: Lavie, A.]] | | [[Category: Petsko GA]] |
| [[Category: Petsko, G A.]] | | [[Category: Ringe D]] |
| [[Category: Ringe, D.]] | |
| [[Category: isomerase(intramolecular oxidoreductase)]]
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| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 00:56:24 2008''
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