Recent structural and mechanistic insights into post-translational enzymatic glycosylation

Enzymatic glycosylation of proteins, a post-transitional modification of great significance, is carried out by diverse glycosyltransferases (GTs) that harness activated sugar donors, typically nucleotide or lipid-phosphate linked species. Recent work has seen a major increase in the study of the 3D structure and reaction mechanism of these enzymes. Key advances include the dissection of the classical O-glycosylating and N-glycosylating apparatus, revealing unusual folds and hitherto unconsidered chemical mechanisms for acceptor activation. There has been considerable success in the application of kinetic isotope effects and quantum simulations to address the controversial issue of the reaction mechanism of retaining GTs. New roles for old modifications, exemplified by potential epigenetic roles for glycosylation, have been discovered and there has also been a plethora of studies into important mammalian glycosylations that play key roles in cellular biology, opening up new targets for chemical intervention approaches.