View source for 8dak


==Crystal structure of the GDP-D-glycero-4-keto-d-lyxo-heptose-3-epimerase from Campylobacter jejuni, serotype HS:3==
<StructureSection load='8dak' size='340' side='right'caption='[[8dak]], [[Resolution|resolution]] 1.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8dak]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Campylobacter_jejuni Campylobacter jejuni]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8DAK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8DAK 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]] 1.5&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=GDP:GUANOSINE-5-DIPHOSPHATE'>GDP</scene>, <scene name='pdbligand=TMA:TETRAMETHYLAMMONIUM+ION'>TMA</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=8dak FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8dak OCA], [https://pdbe.org/8dak PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8dak RCSB], [https://www.ebi.ac.uk/pdbsum/8dak PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8dak ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/F2X702_CAMJU F2X702_CAMJU] Catalyzes the epimerization of the C3' and C5'positions of dTDP-6-deoxy-D-xylo-4-hexulose, forming dTDP-6-deoxy-L-lyxo-4-hexulose.[ARBA:ARBA00001997]
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== Publication Abstract from PubMed ==
Campylobacter jejuni is a human pathogen and one of the leading causes of food poisoning in Europe and the United States. The outside of the bacterium is coated with a capsular polysaccharide that assists in the evasion of the host immune system. Many of the serotyped strains of C. jejuni contain a 6-deoxy-heptose moiety that is biosynthesized from GDP-d-glycero-d-manno-heptose by the successive actions of a 4,6-dehydratase, a C3/C5-epimerase, and a C4-reductase. We identified 18 different C3/C5-epimerases that could be clustered together into three groups at a sequence identity of &gt;89%. Four of the enzymes from the largest cluster (from serotypes HS:3, HS:10, HS:23/36, and HS:41) were shown to only catalyze the epimerization at C3. Three enzymes from the second largest cluster (HS:2, HS:15, and HS:42) were shown to catalyze the epimerization at C3 and C5. Enzymes from the third cluster were not characterized. The three-dimensional structures of the epimerases from serotypes HS:3, HS:23/36, HS:15, and HS:41 were determined to resolutions of 1.5-1.9 A. The overall subunit architecture places these enzymes into the diverse "cupin" superfamily. Within X-ray coordinate error, the immediate regions surrounding the active sites are identical, suggesting that factors extending farther out may influence product outcome. The X-ray crystal structures are consistent with His-67 and Tyr-134 acting as general acid/base catalysts for the epimerization of C3 and/or C5. Two amino acid changes (A76V/C136L) were enough to convert the C3-epimerase from serotype HS:3 to one that could now catalyze the epimerization at both C3 and C5.

C3- and C3/C5-Epimerases Required for the Biosynthesis of the Capsular Polysaccharides from Campylobacter jejuni.,Ghosh MK, Xiang DF, Thoden JB, Holden HM, Raushel FM Biochemistry. 2022 Sep 20;61(18):2036-2048. doi: 10.1021/acs.biochem.2c00364., Epub 2022 Sep 12. PMID:36093987<ref>PMID:36093987</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 8dak" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Campylobacter jejuni]]
[[Category: Large Structures]]
[[Category: Ghosh MK]]
[[Category: Holden HM]]
[[Category: Raushel FM]]
[[Category: Thoden JB]]
[[Category: Xiang DF]]