2vzv

Substrate Complex of Amycolatopsis orientalis exo-chitosanase CsxA E541A with chitosan

spinqualitylabelsall models 2vzv, resolution 2.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2vzv is a 2 chain structure with sequence from "streptomyces_orientalis"_pittenger_and_brigham_1956 "streptomyces orientalis" pittenger and brigham 1956. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GCS Related: 2vzo, 2vzp, 2vzq, 2vzr, 2vzs, 2vzt, 2vzu 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 Family 2 of the glycoside hydrolase classification is one of the largest families. Structurally characterized members of this family include enzymes with beta-galactosidase activity (Escherichia coli LacZ), beta-glucuronidase activity (Homo sapiens GusB), and beta-mannosidase activity (Bacteroides thetaiotaomicron BtMan2A). Here, we describe the structure of a family 2 glycoside hydrolase, CsxA, from Amycolatopsis orientalis that has exo-beta-D-glucosaminidase (exo-chitosanase) activity. Analysis of a product complex (1.85 A resolution) reveals a unique negatively charged pocket that specifically accommodates the nitrogen of nonreducing end glucosamine residues, allowing this enzyme to discriminate between glucose and glucosamine. This also provides structural evidence for the role of E541 as the catalytic nucleophile and D469 as the catalytic acid/base. The structures of an E541A mutant in complex with a natural beta-1,4-D-glucosamine tetrasaccharide substrate and both E541A and D469A mutants in complex with a pNP-beta-D-glucosaminide synthetic substrate provide insight into interactions in the +1 subsite of this enzyme. Overall, a comparison with the active sites of other GH2 enzymes highlights the unique architecture of the CsxA active site, which imparts specificity for its cationic substrate. The structural basis of substrate recognition in an exo-beta-D-glucosaminidase involved in chitosan hydrolysis.,van Bueren AL, Ghinet MG, Gregg K, Fleury A, Brzezinski R, Boraston AB J Mol Biol. 2009 Jan 9;385(1):131-9. Epub 2008 Oct 19. PMID:18976664 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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