Abstract
Bacterial glycoconjugates are widespread and have diverse biological functions. Multiple bacterial glycoproteins are involved in adhesion, invasion or evasion of host defense mechanisms. A range of glycosylation pathways has recently been an object of intense research. Their activity is based on the glycosyltransferases – enzymes that transfer sugar moieties directly to the acceptor protein (sequential glycosylation) or to a lipid carrier from which the glycan is transferred by an oligosaccharyltransferase onto the target protein (en-bloc glycosylation). Successful implementation of complete glycosylation systems in Escherichia coli cells resulted in rapid development of bacterial glycoengineering. Oligosaccharyltransferases are characterized by a broad substrate specificity which may be exploited to produce glycoconjugate vaccines.