O-Glycoligases, a new category of glycoside bond-forming mutant glycosidases, catalyse facile syntheses of isoprimeverosides

摘要

A mutant α-xylosidase that lacks its catalytic acid/base residue efficiently catalyses the synthesis of O-linked isoprimeverosides (Xyl-α-1,6G1cOR) in near quantitative yields. Retaining glycosidases are highly efficient catalysts that hydrolyse glycosidic bonds through a two step, double-displacement mechanism involving a covalent glycosyl-enzyme intermediate (Fig. la). Two key catalytic residues, typically Glu or Asp, play roles in this mechanism.