2rg0

Crystal structure of cellobiohydrolase from Melanocarpus albomyces complexed with cellotetraose

spinqualitylabelsall models 2rg0, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2rg0 is a 4 chain structure with sequence from Melanocarpus albomyces. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CBI, CTT NonStd Res: PCA Related: 2rfw, 2rfy, 2rfz Activity: Cellulose 1,4-beta-cellobiosidase, with EC number 3.2.1.91 Resources: FirstGlance, OCA, RCSB, PDBsum 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 Cellobiohydrolase from Melanocarpus albomyces (Cel7B) is a thermostable, single-module, cellulose-degrading enzyme. It has relatively low catalytic activity under normal temperatures, which allows structural studies of the binding of unmodified substrates to the native enzyme. In this study, we have determined the crystal structure of native Ma Cel7B free and in complex with three different cello-oligomers: cellobiose (Glc(2)), cellotriose (Glc(3)), and cellotetraose (Glc(4)), at high resolution (1.6-2.1 A). In each case, four molecules were found in the asymmetric unit, which provided 12 different complex structures. The overall fold of the enzyme is characteristic of a glycoside hydrolase family 7 cellobiohydrolase, where the loops extending from the core beta-sandwich structure form a long tunnel composed of multiple subsites for the binding of the glycosyl units of a cellulose chain. The catalytic residues at the reducing end of the tunnel are conserved, and the mechanism is expected to be retaining similarly to the other family 7 members. The oligosaccharides in different complex structures occupied different subsite sets, which partly overlapped and ranged from -5 to +2. In four cellotriose and one cellotetraose complex structures, the cello-oligosaccharide also spanned over the cleavage site (-1/+1). There were surprisingly large variations in the amino acid side chain conformations and in the positions of glycosyl units in the different cello-oligomer complexes, particularly at subsites near the catalytic site. However, in each complex structure, all glycosyl residues were in the chair (4C(1)) conformation. Implications in relation to the complex structures with respect to the reaction mechanism are discussed. Crystal structures of Melanocarpus albomyces cellobiohydrolase Cel7B in complex with cello-oligomers show high flexibility in the substrate binding.,Parkkinen T, Koivula A, Vehmaanpera J, Rouvinen J Protein Sci. 2008 Aug;17(8):1383-94. Epub 2008 May 21. PMID:18499583 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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