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From Proteopedia
Anatomy of glycosynthesis: Structure and kinetics of the Humicola insolens Cel7BE197A and E197S glycosynthase mutants
Structural highlights
FunctionGUN1_HUMIN 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 formation of glycoconjugates and oligosaccharides remains one of the most challenging chemical syntheses. Chemo-enzymatic routes using retaining glycosidases have been successfully harnessed but require tight kinetic or thermodynamic control. "Glycosynthases," specifically engineered glycosidases that catalyze the formation of glycosidic bonds from glycosyl donor and acceptor alcohol, are an emerging range of synthetic tools in which catalytic nucleophile mutants are harnessed together with glycosyl fluoride donors to generate powerful and versatile catalysts. Here we present the structural and kinetic dissection of the Humicola insolens Cel7B glycosynthases in which the nucleophile of the wild-type enzyme is mutated to alanine and serine (E197A and E197S). 3-D structures reveal the acceptor and donor subsites and the basis for substrate inhibition. Kinetic analysis shows that the E197S mutant is considerably more active than the corresponding alanine mutant due to a 40-fold increase in k(cat). Anatomy of glycosynthesis: structure and kinetics of the Humicola insolens Cel7B E197A and E197S glycosynthase mutants.,Ducros VM, Tarling CA, Zechel DL, Brzozowski AM, Frandsen TP, von Ossowski I, Schulein M, Withers SG, Davies GJ Chem Biol. 2003 Jul;10(7):619-28. PMID:12890535[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. Loading citation details.. Citations No citations found See AlsoReferences
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