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==X-RAY ANALYSIS OF D-XYLOSE ISOMERASE AT 1.9 ANGSTROMS: NATIVE ENZYME IN COMPLEX WITH SUBSTRATE AND WITH A MECHANISM-DESIGNED INACTIVATOR== | |||
[[Image: | <StructureSection load='9xia' size='340' side='right' caption='[[9xia]], [[Resolution|resolution]] 1.90Å' scene=''> | ||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[9xia]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Streptomyces_rubiginosus Streptomyces rubiginosus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=9XIA OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=9XIA FirstGlance]. <br> | |||
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=DFR:3-DEOXY-3-METHYL-D-FRUCTOSE'>DFR</scene>, <scene name='pdbligand=MN:MANGANESE+(II)+ION'>MN</scene><br> | |||
<tr><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><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><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=9xia FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9xia OCA], [http://www.rcsb.org/pdb/explore.do?structureId=9xia RCSB], [http://www.ebi.ac.uk/pdbsum/9xia PDBsum]</span></td></tr> | |||
<table> | |||
== 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/xi/9xia_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]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The structures of crystalline D-xylose isomerase (D-xylose ketol-isomerase; EC 5.3.1.5) from Streptomyces rubiginosus and of its complexes with substrate and with an active-site-directed inhibitor have been determined by x-ray diffraction techniques and refined to 1.9-A resolution. This study identifies the active site, as well as two metal-binding sites. The metal ions are important in maintaining the structure of the active-site region and one of them binds C3-O and C5-O of the substrate forming a six-membered ring. This study has revealed a very close contact between histidine and C1 of a substrate, suggesting that this is the active-site base that abstracts a proton from substrate. The mechanism-based inhibitor is a substrate analog and is turned over by the enzyme to give a product that alkylates this same histidine, reinforcing our interpretation. The changes in structure of the native enzyme, the enzyme with bound substrate, and the alkylated enzyme indicate that the mechanism involves an "open-chain" conformation of substrate and that the intermediate in the isomerization reaction is probably a cis-ene diol because the active-site histidine is correctly placed to abstract a proton from C1 or C2 of the substrate. A water molecule binds to C1O and C2O of the substrate and so may act as a proton donor or acceptor in the enolization of a ring-opened substrate. | |||
X-ray analysis of D-xylose isomerase at 1.9 A: native enzyme in complex with substrate and with a mechanism-designed inactivator.,Carrell HL, Glusker JP, Burger V, Manfre F, Tritsch D, Biellmann JF Proc Natl Acad Sci U S A. 1989 Jun;86(12):4440-4. PMID:2734296<ref>PMID:2734296</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
==See Also== | |||
*[[D-xylose isomerase|D-xylose isomerase]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
== | |||
== | |||
< | |||
[[Category: Streptomyces rubiginosus]] | [[Category: Streptomyces rubiginosus]] | ||
[[Category: Xylose isomerase]] | [[Category: Xylose isomerase]] | ||
[[Category: Carrell, H L.]] | [[Category: Carrell, H L.]] | ||
[[Category: Glusker, J P.]] | [[Category: Glusker, J P.]] | ||
Revision as of 12:17, 5 June 2014
X-RAY ANALYSIS OF D-XYLOSE ISOMERASE AT 1.9 ANGSTROMS: NATIVE ENZYME IN COMPLEX WITH SUBSTRATE AND WITH A MECHANISM-DESIGNED INACTIVATORX-RAY ANALYSIS OF D-XYLOSE ISOMERASE AT 1.9 ANGSTROMS: NATIVE ENZYME IN COMPLEX WITH SUBSTRATE AND WITH A MECHANISM-DESIGNED INACTIVATOR
Structural highlights
Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe structures of crystalline D-xylose isomerase (D-xylose ketol-isomerase; EC 5.3.1.5) from Streptomyces rubiginosus and of its complexes with substrate and with an active-site-directed inhibitor have been determined by x-ray diffraction techniques and refined to 1.9-A resolution. This study identifies the active site, as well as two metal-binding sites. The metal ions are important in maintaining the structure of the active-site region and one of them binds C3-O and C5-O of the substrate forming a six-membered ring. This study has revealed a very close contact between histidine and C1 of a substrate, suggesting that this is the active-site base that abstracts a proton from substrate. The mechanism-based inhibitor is a substrate analog and is turned over by the enzyme to give a product that alkylates this same histidine, reinforcing our interpretation. The changes in structure of the native enzyme, the enzyme with bound substrate, and the alkylated enzyme indicate that the mechanism involves an "open-chain" conformation of substrate and that the intermediate in the isomerization reaction is probably a cis-ene diol because the active-site histidine is correctly placed to abstract a proton from C1 or C2 of the substrate. A water molecule binds to C1O and C2O of the substrate and so may act as a proton donor or acceptor in the enolization of a ring-opened substrate. X-ray analysis of D-xylose isomerase at 1.9 A: native enzyme in complex with substrate and with a mechanism-designed inactivator.,Carrell HL, Glusker JP, Burger V, Manfre F, Tritsch D, Biellmann JF Proc Natl Acad Sci U S A. 1989 Jun;86(12):4440-4. PMID:2734296[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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