|Title||A BETA-GLUCOSIDASE FROM AN AGROBACTERIUM SP - STRUCTURE AND BIOCHEMISTRY|
|Publication Type||Journal Article|
|Year of Publication||1993|
|Authors||TRIMBUR, D, WARREN, RAJ, Withers, SG|
|Journal||ACS SYMPOSIUM SERIES|
The beta-glucosidase (Abg) from an Agrobacterium sp. is a homodimer of monomers of molecular weight 51, 192. It is a retaining enzyme catalysing glycoside hydrolysis by a double-displacement mechanism in which an enzymic nucleophile (Glu358) attacks the substrate forming a glucosyl-enzyme intermediate which is then hydrolysed releasing beta-glucose. Comparisons of properties of the wild-type enzyme and its Glu358Asp mutant indicate that the principal roles for Glu358 are transition state stabilization and formation of the glycosyl-enzyme covalent intermediate, but not substrate binding. Other critical residues for enzyme activity are Gly360 and Asp374 and all three of these amino acids are conserved in the enzymes of family BGA of beta-glucosidases.