1bvw

CELLOBIOHYDROLASE II (CEL6A) FROM HUMICOLA INSOLENS

spinqualitylabelsall models 1bvw, resolution 1.92Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1bvw is a 1 chain structure with sequence from Atcc 16454. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GOL, MAN, MG, NAG Activity: Cellulose 1,4-beta-cellobiosidase (non-reducing end), with EC number 3.2.1.91 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum Function [GUX6_HUMIN] Plays a central role in the recycling of plant biomass. The biological conversion of cellulose to glucose generally requires three types of hydrolytic enzymes: (1) Endoglucanases which cut internal beta-1,4-glucosidic bonds; (2) Exocellobiohydrolases that cut the dissaccharide cellobiose from the non-reducing end of the cellulose polymer chain; (3) Beta-1,4-glucosidases which hydrolyze the cellobiose and other short cello-oligosaccharides to glucose. 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 The three-dimensional structure of the catalytic core of the family 6 cellobiohydrolase II, Cel6A (CBH II), from Humicola insolens has been determined by X-ray crystallography at a resolution of 1.92 A. The structure was solved by molecular replacement using the homologous Trichoderma reesei CBH II as a search model. The H. insolens enzyme displays a high degree of structural similarity with its T. reesei equivalent. The structure features both O- (alpha-linked mannose) and N-linked glycosylation and a hexa-co-ordinate Mg2+ ion. The active-site residues are located within the enclosed tunnel that is typical for cellobiohydrolase enzymes and which may permit a processive hydrolysis of the cellulose substrate. The close structural similarity between the two enzymes implies that kinetics and chain-end specificity experiments performed on the H. insolens enzyme are likely to be applicable to the homologous T. reesei enzyme. These cast doubt on the description of cellobiohydrolases as exo-enzymes since they demonstrated that Cel6A (CBH II) shows no requirement for non-reducing chain-ends, as had been presumed. There is no crystallographic evidence in the present structure to support a mechanism involving loop opening, yet preliminary modelling experiments suggest that the active-site tunnel of Cel6A (CBH II) is too narrow to permit entry of a fluorescenyl-derivatized substrate, known to be a viable substrate for this enzyme. Crystal structure of the catalytic core domain of the family 6 cellobiohydrolase II, Cel6A, from Humicola insolens, at 1.92 A resolution.,Varrot A, Hastrup S, Schulein M, Davies GJ Biochem J. 1999 Jan 15;337 ( Pt 2):297-304. PMID:9882628 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Cellobiohydrolase

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