On expanding the repertoire of glycosynthases: Mutant beta-galactosidases forming beta-(1,6)-linkages

Oligosaccharide synthesis by enzymatic processes offers the potential for thrusting oligosaccharides to the forefront of pharmaceutical research, in part, due to expedient and scalable reaction protocols. Glycosynthases are an emerging class of mutant enzymes capable of synthesizing glycosidic linkages in high yield. We report a new glycosynthase enzyme generated by a point mutation of E. coli beta-galactosidase that condenses alpha-galactosyl fluoride with aryl glucosides forming a beta-(1,6) glycosidic linkage. A further point mutation within the enzyme, proximal to the active site, increases the yields significantly.