Enzymatic transglycosylation of xylose using a glycosynthase.

The application of the hyperactive glycosynthase derived from Agrobacterium sp. beta-glucosidase (AbgE358G-2F6) to the synthesis of xylo-oligosaccharides by using alpha-D-xylopyranosyl fluoride as donor represents the first successful use of glycosynthase technology for xylosyl transfer. Transfer to p-nitrophenyl beta-D-glucopyranoside yields di- and trisaccharide products with beta-(1-->4) linkages in 63% and 35% yields, respectively. By contrast, transfer to p-nitrophenyl beta-D-xylopyranoside yielded the beta-(1-->3) linked disaccharide and beta-D-Xyl-(1-->4)-beta-D-Xyl-(1-->3)-beta-D-Xyl-pNP as major products in 42% and 30% yields, respectively. Transfer of xylose to beta-D-Xyl-(1-->4)-beta-D-Xyl-pNP yielded the beta-(1-->4) linked trisaccharide in 98% yield, thereby indicating that transfers to xylo-disaccharides occur with formation of beta-(1-->4) bonds. Xylosylation of carbamate-protected deoxyxylonojirimycin produced a mixture of di- and tri-'saccharide' products in modest yields.