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[[Image:1xym.png|left|200px]]
==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==
<StructureSection load='1xym' size='340' side='right' caption='[[1xym]], [[Resolution|resolution]] 1.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1xym]] is a 2 chain structure with 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]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1XYM FirstGlance]. <br>
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><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><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=1xym FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1xym OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1xym RCSB], [http://www.ebi.ac.uk/pdbsum/1xym 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/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/chain_selection.php?pdb_ID=2ata ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
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 &lt; or = 0.5-1.0 mM for one Mg2+ and &lt; 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)


{{STRUCTURE_1xym|  PDB=1xym  |  SCENE=  }}
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:7906142<ref>PMID:7906142</ref>


===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===
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
 
</div>
{{ABSTRACT_PUBMED_7906142}}
 
==About this Structure==
[[1xym]] is a 2 chain structure with 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].


==See Also==
==See Also==
*[[D-xylose isomerase|D-xylose isomerase]]
*[[D-xylose isomerase|D-xylose isomerase]]
 
== References ==
==Reference==
<references/>
<ref group="xtra">PMID:007906142</ref><references group="xtra"/>
__TOC__
</StructureSection>
[[Category: Streptomyces olivochromogenes]]
[[Category: Streptomyces olivochromogenes]]
[[Category: Xylose isomerase]]
[[Category: Xylose isomerase]]
Retrieved from "https://proteopedia.org/1xym"