InterPro domain: IPR006009

The murG gene of Escherichia coli encodes the N-acetylglucosaminyltransferase, UDP-N-acetylglucosamine--N-acetylmuramyl-(pentapeptide) pyrophosphoryl-undecaprenol N-acetylglucosamine transferase, responsible for the final step in the formation of the lipid-linked disaccharide-pentapeptide subunit of peptidoglycan [ 1 ]. It transfers N-acetyl-D-glucosamine (GlcNAc) from UDP-GlcNAc to the C4 hydroxyl of a lipid-linked N-acetylmuramoyl pentapeptide (NAM). The resulting disaccharide is then transported across the cell membrane, where it is polymerized into NAG-NAM cell-wall repeat structure. The enzyme is peripherally associated with the inner face of the cytoplasmic membrane. Therefore, the peptidoglycan subunit is completely assembled before it traverses the cytoplasmic membrane [ 2 ].

MurG belongs to the GT-B structural superfamily of glycoslytransferases, which have characteristic N- and C-terminal domains, each containing a typical Rossmann fold [ 3 ]. The two domains have high structural homology despite minimal sequence homology. The large cleft that separates the two domains includes the catalytic centre and permits a high degree of flexibility.

1. E. Coli MurG: a paradigm for a superfamily of glycosyltransferases. Curr Drug Targets Infect Disord 1, 201-13
2. The final step of peptidoglycan subunit assembly in Escherichia coli occurs in the cytoplasm. J. Bacteriol. 175, 1841-3
3. The 1.9 A crystal structure of Escherichia coli MurG, a membrane-associated glycosyltransferase involved in peptidoglycan biosynthesis. Protein Sci. 9, 1045-52