 Mutants in which these residues were replaced in BGlu0 beta-glucosidase hydrolyzed cellotetraose and cellopentaose with k ( cat ) /K ( m ) values similar to those of the wild type enzyme . Score: 0.00 Title: QM/MM studies on the glycosylation mechanism of rice BGlu0 beta-glucosidase . Journal: J Mol Graph Model Year: 0000 Type: MEDLINE Literature: oryza Field: abstract Doc ID: pub00000000 Accession (PMID): 00000000 Abstract: The quantum-mechanical/molecular-mechanical ( QM/MM ) method was used to study the glycosylation mechanism of rice BGlu0 beta-glucosidase in complex with laminaribiose . The calculation results reveal that the glycosylation step experiences a concerted process from the reactant to the glycosyl-enzyme complex with an activation barrier of 00 . 0 kcal/mol , in which an oxocarbenium cation-like transition state ( TS ) is formed . At the TS , the terminal saccharide residue planarizes toward the half-chair conformation , and the glycosidic bond cleavage is promoted by the attacks of proton donor ( E000 ) on glycosidic oxygen and nucleophilic residue ( E000 ) on the anomeric carbon of laminaribiose . Both the nucleophilic glutamate ( E000 ) and acid/base catalyst ( E000 ) establish shorter hydrogen bridges with the C-hydroxyl groups of sugar ring , which play an important role in the catalytic reaction of rice BGlu0 beta-glucosidase . Matching Sentences: [ Sen. 0, subscore: 0.00 ]: The quantum-mechanical/molecular-mechanical ( QM/MM ) method was used to study the glycosylation mechanism of rice BGlu0 beta-glucosidase in complex with laminaribiose . 