2his
From Proteopedia
CELLULOMONAS FIMI XYLANASE/CELLULASE DOUBLE MUTANT E127A/H205N WITH COVALENT CELLOBIOSE
Structural highlights
FunctionGUX_CELFI Hydrolyzes both cellulose and xylan. Has also weak endoglucanase activity. 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 PubMedThe catalytic mechanism of 'retaining' beta-glycosidases has been the subject of considerable interest and debate for many years. The visualization of a covalent glycosyl enzyme intermediate by X-ray crystallography was first accomplished with a saccharide substrate substituted with fluorine at its 2-position. The structure implicated major roles for residue His 205 and for the 2-hydroxyl position of the proximal saccharide in binding and catalysis. Here we have studied the kinetic behavior of various His 205 mutants. One of these mutants, a double mutant H205N/E127A, has been used to stabilize a covalent glycosyl-enzyme intermediate involving an unsubstituted sugar, permitting crystallographic analysis of the interactions between its 2-hydroxyl group and the enzyme. Insights into transition state stabilization of the beta-1,4-glycosidase Cex by covalent intermediate accumulation in active site mutants.,Notenboom V, Birsan C, Nitz M, Rose DR, Warren RA, Withers SG Nat Struct Biol. 1998 Sep;5(9):812-8. PMID:9731776[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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