4c7f | pdb_00004c7f

Structure and activity of the GH20 beta-N-acetylhexosaminidase from Streptomyces coelicolor A3(2)

spinqualitylabelsall models 4c7f, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4c7f is a 2 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: EDO, GC2 Related: 4c7d, 4c7g Activity: Beta-N-acetylhexosaminidase, with EC number 3.2.1.52 Resources: FirstGlance, OCA, RCSB, PDBsum Publication Abstract from PubMed beta-N-acetylhexosaminidases (HEX) are glycosidases that catalyze the glycosidic linkage hydrolysis of gluco- and galacto-configured N-acetyl-beta-D-hexosaminides. These enzymes are important in human physiology and are candidates for the biocatalytic production of carbohydrates and glycomimetics. In this study, the three-dimensional structure of the wild-type and catalytically impaired E302Q HEX variant from the soil bacterium Streptomyces coelicolor A3(2) (ScHEX) were solved in ligand-free forms and in the presence of 6-acetamido-6-deoxy-castanospermine (6-Ac-Cas). The E302Q variant was also trapped as an intermediate with oxazoline bound to the active center. Crystallographic evidence highlights structural variations in the loop 3 environment, suggesting conformational heterogeneity for important active-site residues of this GH20 family member. The enzyme was investigated for its beta-N-acetylhexosaminidase activity toward chitooligomers and pNP-acetyl gluco- and galacto-configured N-acetyl hexosaminides. Kinetic analyses confirm the beta(1-4) glycosidic linkage substrate preference and HPLC profiles support an exoglycosidase mechanism, where the enzyme cleaves sugars from the non-reducing end of substrates. ScHEX possesses significant activity toward chitooligosaccharides of varying degrees of polymerization and the final hydrolytic reaction yielded pure GlcNAc without any byproduct, promising high applicability for the enzymatic production of this highly valued chemical. Thermostability and activation assays further suggest efficient conditions applicable to the enzymatic production of GlcNAc from chitooligomers. Structure and activity of the Streptomyces coelicolor A3(2) beta-N-acetylhexosaminidase provides further insight into GH20 family catalysis and inhibition.,Nguyen Thi N, Offen WA, Shareck F, Davies GJ, Doucet N Biochemistry. 2014 Feb 21. PMID:24559145 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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