Substrate-induced conformational changes in glycosyltransferases

摘要: Oligosaccharide chains of glycoproteins, glycolipids and glycosaminoglycans are synthesized by glycosyltransferases the transfer specific glycosyl moieties from activated sugar-nucleotide donors to acceptors. Structural studies on several these enzymes have shown that one or two flexible loops at substrate-binding site undergo a marked conformational change an open closed conformation binding donor substrate. This change, in which loop acts as lid covering bound substrate, creates acceptor-binding site. After unit is transferred acceptor, saccharide product ejected reverts its native conformation, thereby releasing remaining nucleotide moiety. The specificity sugar determined few residues sugar-nucleotide-binding pocket enzyme conserved among family members different species.