1rkx

<table><tr><td colspan='2'>[[1rkx]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/"bacillus_pseudotuberkulosis"_(sic)_pfeiffer_1889 "bacillus pseudotuberkulosis" (sic) pfeiffer 1889]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1RKX OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=1RKX FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=NAD:NICOTINAMIDE-ADENINE-DINUCLEOTIDE'>NAD</scene></td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">ascB ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=633 "Bacillus pseudotuberkulosis" (sic) Pfeiffer 1889])</td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/CDP-glucose_4,6-dehydratase CDP-glucose 4,6-dehydratase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.1.45 4.2.1.45] </span></td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=1rkx FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1rkx OCA], [http://pdbe.org/1rkx PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1rkx RCSB], [http://www.ebi.ac.uk/pdbsum/1rkx PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1rkx ProSAT]</span></td></tr>

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== Publication Abstract from PubMed ==

CDP-D-glucose 4,6-dehydratase catalyzes the conversion of CDP-D-glucose to CDP-4-keto-6-deoxyglucose in an NAD(+)-dependent manner. The product of this conversion is a building block for a variety of primary antigenic determinants in bacteria, possibly implicated directly in reactive arthritis. Here, we describe the solution of the high-resolution crystal structure of CDP-D-glucose 4,6-dehydratase from Yersinia pseudotuberculosis in the resting state. This structure represents the first CDP nucleotide utilizing dehydratase of the short-chain dehydrogenase/reductase (SDR) family to be determined, as well as the first tetrameric structure of the subfamily of SDR enzymes in which NAD(+) undergoes a full reaction cycle. On the basis of a comparison of this structure with structures of homologous enzymes, a chemical mechanism is proposed in which Tyr157 acts as the catalytic base, initiating hydride transfer by abstraction of the proton from the sugar 4'-hydroxyl. Concomitant with the removal of the proton from the 4'-hydroxyl oxygen, the sugar 4'-hydride is transferred to the B face of the NAD(+) cofactor, forming the reduced cofactor and a CDP-4-keto-d-glucose intermediate. A conserved Lys161 most likely acts to position the NAD(+) cofactor so that hydride transfer is favorable and/or to reduce the pK(a) of Tyr157. Following substrate oxidation, we propose that Lys134, acting as a base, would abstract the 5'-hydrogen of CDP-4-keto-D-glucose, priming the intermediate for the spontaneous loss of water. Finally, the resulting Delta(5,6)-glucoseen intermediate would be reduced suprafacially by the cofactor, and reprotonation at C-5' is likely mediated by Lys134.

Crystal structure at 1.8 A resolution of CDP-D-glucose 4,6-dehydratase from Yersinia pseudotuberculosis.,Vogan EM, Bellamacina C, He X, Liu HW, Ringe D, Petsko GA Biochemistry. 2004 Mar 23;43(11):3057-67. PMID:15023057<ref>PMID:15023057</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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== References ==

<references/>

[[Category: CDP-glucose 4,6-dehydratase]]

[[Category: Bellamacina, C]]

[[Category: He, X]]

[[Category: Liu, H W]]

[[Category: Petsko, G A]]

[[Category: Ringe, D]]

[[Category: Vogan, E M]]

[[Category: Sdr]]