S. Fort et al., Highly efficient synthesis of beta(1 -> 4)-oligo- and -polysaccharides using a mutant cellulase, J AM CHEM S, 122(23), 2000, pp. 5429-5437
This report describes an efficient chemoenzymatic synthesis of a variety of
regioselectively modified beta(1-->4)-oligo- and -polysaccharides. This su
ccessfull approach was based on: (i) the use of a "glycosynthase" which is
a Glu-197-Ala nucleophile mutant of the retaining cellulase endoglucanase I
(Cel7B) from Humicola insolens and (ii) the rational design of modified ac
ceptor and donor molecules through a careful examination of information giv
en by the X-ray structures of wild type and mutated enzymes. The mutant was
able to catalyze, in high yield, the regio- and stereoselective glycosylat
ion of alpha-glycobiosyl fluorides both unsubstituted and modified with var
ious mono- and disaccharide accepters, as well as the polymerization of the
se donors through a single-step inverting mechanism.