InterPro: IPR003835 Glycosyl transferase, family 19

The biosynthesis of disaccharides, oligosaccharides and polysaccharides involves the action of hundreds of different glycosyltransferases. These enzymes catalyse the transfer of sugar moieties from activated donor molecules to specific acceptor molecules, forming glycosidic bonds. A classification of glycosyltransferases using nucleotide diphospho-sugar, nucleotide monophospho-sugar and sugar phosphates (EC:2.4.1.-) and related proteins into distinct sequence based families has been described [1]. This classification is available on the CAZy (CArbohydrate-Active EnZymes) web site [2]. The same three-dimensional fold is expected to occur within each of the families. Because 3-D structures are better conserved than sequences, several of the families defined on the basis of sequence similarities may have similar 3-D structures and therefore form 'clans'.

These enzymes belong to the glycosyltransferase family 19 GT19. Lipid-A-disaccharide synthetase EC:2.4.1.182 is involved with acyl-[acyl-carrier-protein]--UDP-N-acetylglucosamine O-acyltransferase EC:2.3.1.129 and tetraacyldisaccharide 4'-kinase EC:2.7.1.130 in the biosynthesis of the phosphorylated glycolipid, lipid A, in the outer membrane of Escherichia coli and other bacteria. These enzymes catalyse the first disaccharide step in the synthesis of lipid-A-disaccharide.