1ytw
From Proteopedia
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YERSINIA PTPASE COMPLEXED WITH TUNGSTATE
Overview
X-ray crystal structures of the Yersinia tyrosine phosphatase (PTPase) in, complex with tungstate and nitrate have been solved to 2. 4-A resolution., Tetrahedral tungstate, WO42-, is a competitive inhibitor of the enzyme and, is isosteric with the substrate and product of the catalyzed reaction., Planar nitrate, NO3-, is isosteric with the PO3 moiety of a, phosphotransfer transition state. The crystal structures of the Yersinia, PTPase with and without ligands, together with biochemical data, permit, modeling of key steps along the reaction pathway. These energy-minimized, models are consistent with a general acid-catalyzed, in-line displacement, of the phosphate moiety to Cys403 on the enzyme, followed by attack by a, nucleophilic water molecule to release orthophosphate. This nucleophilic, water molecule is identified in the crystal structure of the nitrate, complex. The active site structure of the PTPase is compared to alkaline, phosphatase, which employs a similar phosphomonoester hydrolysis, mechanism. Both enzymes must stabilize charges at the nucleophile, the PO3, moiety of the transition state, and the leaving group. Both an associative, (bond formation preceding bond cleavage) and a dissociative (bond cleavage, preceding bond formation) mechanism were modeled, but a dissociative-like, mechanism is favored for steric and chemical reasons. Since nearly all of, the 47 invariant or highly conserved residues of the PTPase domain are, clustered at the active site, we suggest that the mechanism postulated for, the Yersinia enzyme is applicable to all the PTPases.
About this Structure
1YTW is a Single protein structure of sequence from Yersinia enterocolitica with WO4 and SO4 as ligands. Active as Protein-tyrosine-phosphatase, with EC number 3.1.3.48 Structure known Active Sites: PL and WPD. Full crystallographic information is available from OCA.
Reference
The X-ray crystal structures of Yersinia tyrosine phosphatase with bound tungstate and nitrate. Mechanistic implications., Fauman EB, Yuvaniyama C, Schubert HL, Stuckey JA, Saper MA, J Biol Chem. 1996 Aug 2;271(31):18780-8. PMID:8702535
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