Glycosyltransferase structural biology and its role in the design of catalysts for glycosylation

► Glycosyltransferases (GTs) are an important class of enzyme as both drug targets and synthetic catalysts. ► Two predominant GT folds (GT-A and GT-B) enable the connection between a vast range of sugar donors and acceptors representing a wide array of regiospecificities and stereospecificities. ► Although few 'general' rules exist, rational engineering has led to GTs with altered specificities (sugar donor and/or acceptors). ► In the context of engineered GTs, an enhancement of promiscuity often correlates with an increase in overall proficiency.