3itc

Crystal structure of Sco3058 with bound citrate and glycerol

spinqualitylabelsall models 3itc, resolution 1.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3itc is a 1 chain structure with sequence from "actinomyces_coelicolor"_(muller_1908)_lieske_1921 "actinomyces coelicolor" (muller 1908) lieske 1921. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CIT, GOL, ZN Related: 3isi Gene: SCO3058, SCBAC19G2.13c ("Actinomyces coelicolor" (Muller 1908) Lieske 1921) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Human renal dipeptidase, an enzyme associated with glutathione metabolism and the hydrolysis of beta-lactams, is similar in sequence to a cluster of approximately 400 microbial proteins currently annotated as nonspecific dipeptidases within the amidohydrolase superfamily. The closest homologue to the human renal dipeptidase from a fully sequenced microbe is Sco3058 from Streptomyces coelicolor. Dipeptide substrates of Sco3058 were identified by screening a comprehensive series of l-Xaa-l-Xaa, l-Xaa-d-Xaa, and d-Xaa-l-Xaa dipeptide libraries. The substrate specificity profile shows that Sco3058 hydrolyzes a broad range of dipeptides with a marked preference for an l-amino acid at the N-terminus and a d-amino acid at the C-terminus. The best substrate identified was l-Arg-d-Asp (k(cat)/K(m) = 7.6 x 10(5) M(-1) s(-1)). The three-dimensional structure of Sco3058 was determined in the absence and presence of the inhibitors citrate and a phosphinate mimic of l-Ala-d-Asp. The enzyme folds as a (beta/alpha)(8) barrel, and two zinc ions are bound in the active site. Site-directed mutagenesis was used to probe the importance of specific residues that have direct interactions with the substrate analogues in the active site (Asp-22, His-150, Arg-223, and Asp-320). The solvent viscosity and kinetic effects of D(2)O indicate that substrate binding is relatively sticky and that proton transfers do not occurr during the rate-limiting step. A bell-shaped pH-rate profile for k(cat) and k(cat)/K(m) indicated that one group needs to be deprotonated and a second group must be protonated for optimal turnover. Computational docking of high-energy intermediate forms of l/d-Ala-l/d-Ala to the three-dimensional structure of Sco3058 identified the structural determinants for the stereochemical preferences for substrate binding and turnover. Structure, Mechanism, and Substrate Profile for Sco3058: The Closest Bacterial Homologue to Human Renal Dipeptidase .,Cummings JA, Nguyen TT, Fedorov AA, Kolb P, Xu C, Fedorov EV, Shoichet BK, Barondeau DP, Almo SC, Raushel FM Biochemistry. 2009 Dec 29. PMID:20000809 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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