undecaprenyldiphospho-muramoylpentapeptide beta-N-acetylglucosaminyltransferase. MurG (EC 2.4.1.227) is an N-acetylglucosaminyltransferase, the last enzyme involved in the intracellular phase of peptidoglycan biosynthesis. 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. MurG belongs to the GT-B structural superfamily of glycoslytransferases, which have characteristic N- and C-terminal domains, each containing a typical Rossmann fold. The two domains have high structural homology despite minimal sequence homology. The large cleft that separates the two domains includes the catalytic center and permits a high degree of flexibility.
Glycosyltransferase family 28 C-terminal domain. The glycosyltransferase family 28 includes monogalactosyldiacylglycerol synthase (EC 2.4.1.46) and UDP-N-acetylglucosamine transferase (EC 2.4.1.-). Structural analysis suggests the C-terminal domain contains the UDP-GlcNAc binding site.
beta-diglucosyldiacylglycerol synthase and similar proteins. beta-diglucosyldiacylglycerol synthase (processive diacylglycerol beta-glucosyltransferase EC 2.4.1.315) is involved in the biosynthesis of both the bilayer- and non-bilayer-forming membrane glucolipids. This family of glycosyltransferases also contains plant major galactolipid synthase (chloroplastic monogalactosyldiacylglycerol synthase 1 EC 2.4.1.46). Glycosyltransferases catalyze the transfer of sugar moieties from activated donor molecules to specific acceptor molecules, forming glycosidic bonds. The acceptor molecule can be a lipid, a protein, a heterocyclic compound, or another carbohydrate residue. The structures of the formed glycoconjugates are extremely diverse, reflecting a wide range of biological functions. The members of this family share a common GTB topology, one of the two protein topologies observed for nucleotide-sugar-dependent glycosyltransferases. GTB proteins have distinct N- and C- terminal domains each containing a typical Rossmann fold. The two domains have high structural homology despite minimal sequence homology. The large cleft that separates the two domains includes the catalytic center and permits a high degree of flexibility.