Emerging structural insights into glycosyltransferase-mediated synthesis of glycans
Glycans linked to proteins and lipids play key roles in biology; thus, accurate replication of cellular glycans is crucial for maintaining function following cell division. Several recent crystal structures of glycosyltransferases with bound acceptor substrates reveal that these enzymes have common core structures that function as scaffolds upon which variable loops are inserted to confer substrate specificity and correctly orient the nucleophilic hydroxyl group. K. W. Moremen and R. S. Haltiwanger in Nature Chemical Biology review argue that the varied approaches for acceptor binding site assembly suggest that an ongoing evolution of these loop regions provides templates for assembly of the diverse glycan structures observed in biology.