1dym
HUMICOLA INSOLENS ENDOCELLULASE CEL7B (EG 1) E197A MUTANT ENDOGLUCANASE, HYDROLASE, CELLULASE, CELLULOSE DEGRADATION, GLYCOSIDE HYDROLASE FAMILY 7, GLYCOSYNTHASE
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OverviewOverview
Cellulose is the major polysaccharide component of the plant cell wall and, the most abundant naturally produced macromolecule on Earth. The enzymic, degradation of cellulose, by cellulases, is therefore of great, environmental and commercial significance. Cellulases are found in 12 of, the glycoside hydrolase families classified according to their amino acid, sequence similarities. Endoglucanase I (Cel7B), from the soft-rot fungus, Humicola insolens, is a family 7 enzyme. The structure of the native form, of Cel7B from H. insolens at 2.2 A resolution has been solved by molecular, replacement using the known Trichoderma reesei cellobiohydrolase I [Divne, Stahlberg, Reinikainen, Ruohonen, Pettersson, Knowles, Teeri and Jones, (1994) Science 265, 524-528] structure as the search model. Cel7B, catalyses hydrolysis of the beta-1,4 glycosidic linkages in cellulose with, net retention of anomeric configuration. The catalytic nucleophile at the, active site of Cel7B has been identified as Glu-197 by trapping of a, 2-deoxy-2-fluorocellotriosyl enzyme intermediate and identification of the, labelled peptide in peptic digests by tandem MS. Site-directed mutagenesis, of both Glu-197 and the prospective catalytic acid, Glu-202, results in, inactive enzyme, confirming the critical role of these groups for, catalysis.
About this StructureAbout this Structure
1DYM is a Single protein structure of sequence from Humicola insolens with NAG as ligand. Active as Cellulase, with EC number 3.2.1.4 Structure known Active Site: ACI. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of the family 7 endoglucanase I (Cel7B) from Humicola insolens at 2.2 A resolution and identification of the catalytic nucleophile by trapping of the covalent glycosyl-enzyme intermediate., MacKenzie LF, Sulzenbacher G, Divne C, Jones TA, Woldike HF, Schulein M, Withers SG, Davies GJ, Biochem J. 1998 Oct 15;335 ( Pt 2):409-16. PMID:9761741
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