Peptidoglycan glycosyltransferase (PGT) (PGT)

Peptidoglycan glycosyltransferase (PGT), commonly referred to as bacterial cell wall transglycosylase, is an essential enzyme responsible for the polymerization of glycan chains during peptidoglycan biosynthesis [1]. It catalyzes the transfer of the disaccharide-pentapeptide unit from the lipid-linked precursor, Lipid II, to the nascent peptidoglycan chain, forming β-1,4-glycosidic bonds [2]. This activity is crucial for maintaining the structural integrity of the bacterial cell wall, which protects the organism from osmotic lysis [3]. The enzyme is typically found as a domain within Class A Penicillin-Binding Proteins (PBPs) or as standalone monofunctional glycosyltransferases (MGTs) [1, 4]. Because it is located on the external surface of the cytoplasmic membrane and has no human homolog, it is considered a high-priority target for novel antibiotic development [3]. While the natural product moenomycin is a potent direct inhibitor, its clinical use is limited by poor pharmacokinetics, though other antibiotics like vancomycin effectively block this pathway by sequestering the enzyme's substrate [5]. The development of new direct inhibitors is a major focus in overcoming multi-drug resistant bacterial infections [3]. Challenges in targeting this enzyme include the complexity of its Lipid II substrate and the difficulty of drug penetration through the Gram-negative outer membrane [4].

Other names

Bacterial cell wall transglycosylaseTransglycosylaseGlycosyltransferase family 51Monofunctional peptidoglycan glycosyltransferaseMGTPBP transglycosylase domain

Direct inhibition of glycosyltransferase activity via substrate mimicry; Indirect inhibition via sequestration of the Lipid II substrate.