View source for 2jbv


==Crystal structure of choline oxidase reveals insights into the catalytic mechanism==
<StructureSection load='2jbv' size='340' side='right'caption='[[2jbv]], [[Resolution|resolution]] 1.86&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2jbv]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Arthrobacter_globiformis Arthrobacter globiformis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2JBV OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2JBV 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]] 1.86&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=DMS:DIMETHYL+SULFOXIDE'>DMS</scene>, <scene name='pdbligand=FAO:[[(2R,3S,4S)-5-[(4aS,10S,10aR)-7,8-dimethyl-2,4-dioxo-1,4a,5,10a-tetrahydrobenzo[g]pteridin-10-yl]-2,3,4-trihydroxy-pentoxy]-hydroxy-phosphoryl]+[(2R,3S,4R,5R)-5-(6-aminopurin-9-yl)-3,4-dihydroxy-oxolan-2-yl]methyl+hydrogen+phosphate'>FAO</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=2jbv FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2jbv OCA], [https://pdbe.org/2jbv PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2jbv RCSB], [https://www.ebi.ac.uk/pdbsum/2jbv PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2jbv ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CHOX_ARTGO CHOX_ARTGO] Catalyzes the two-step oxidative conversion of choline to glycine-betaine with betaine aldehyde as an intermediate. Glycine-betaine accumulates to high levels in the cytoplasm of cells to prevent dehydration and plasmolysis in adverse hyperosmotic environments. Accepts either choline or the reaction intermediate betaine-aldehyde as substrate.<ref>PMID:12795615</ref> 
== 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/jb/2jbv_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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=2jbv ConSurf].
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== Publication Abstract from PubMed ==
Choline oxidase catalyzes the oxidation of choline to glycine betaine, a compatible solute that accumulates in pathogenic bacteria and plants so they can withstand osmotic and temperature stresses. The crystal structure of choline oxidase was determined and refined to a resolution of 1.86 A with data collected at 100 K using synchrotron X-ray radiation. The structure reveals a covalent linkage between His99 Nepsilon2 and FAD C8M atoms, and a 123 A3 solvent-excluded cavity adjacent to the re face of the flavin. A hypothetical model for choline docked into the cavity suggests that several aromatic residues and Glu312 may orient the cationic substrate for efficient catalysis. The role of the negative charge on Glu312 was investigated by engineering variant enzymes in which Glu312 was replaced with alanine, glutamine, or aspartate. The Glu312Ala enzyme was inactive. The Glu312Gln enzyme exhibited a Kd value for choline at least 500 times larger than that of the wild-type enzyme. The Glu312Asp enzyme had a kcat/KO2 value similar to that of the wild-type enzyme but kcat and kcat/Km values that were 230 and 35 times lower, respectively, than in the wild-type enzyme. These data are consistent with the spatial location of the negative charge on residue 312 being important for the oxidation of the alcohol substrate. Solvent viscosity and substrate kinetic isotope effects suggest the presence of an internal equilibrium in the Glu312Asp enzyme prior to the hydride transfer reaction. Altogether, the crystallographic and mechanistic data suggest that Glu312 is important for binding and positioning of the substrate in the active site of choline oxidase.

Role of Glu312 in binding and positioning of the substrate for the hydride transfer reaction in choline oxidase.,Quaye O, Lountos GT, Fan F, Orville AM, Gadda G Biochemistry. 2008 Jan 8;47(1):243-56. Epub 2007 Dec 12. PMID:18072756<ref>PMID:18072756</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 2jbv" style="background-color:#fffaf0;"></div>

==See Also==
*[[Choline Oxidase|Choline Oxidase]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Arthrobacter globiformis]]
[[Category: Large Structures]]
[[Category: Fan F]]
[[Category: Gadda G]]
[[Category: Lountos GT]]
[[Category: Orville AM]]