phosphatidyl-myo-inositol mannosyltransferase. This family is most closely related to the GT4 family of glycosyltransferases and named after PimA in Propionibacterium freudenreichii, which is involved in the biosynthesis of phosphatidyl-myo-inositol mannosides (PIM) which are early precursors in the biosynthesis of lipomannans (LM) and lipoarabinomannans (LAM), and catalyzes the addition of a mannosyl residue from GDP-D-mannose (GDP-Man) to the position 2 of the carrier lipid phosphatidyl-myo-inositol (PI) to generate a phosphatidyl-myo-inositol bearing an alpha-1,2-linked mannose residue (PIM1). 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. This group of glycosyltransferases is most closely related to the previously defined glycosyltransferase family 1 (GT1). The members of this family may transfer UDP, ADP, GDP, or CMP linked sugars. The diverse enzymatic activities among members of this family reflect a wide range of biological functions. The protein structure available for this family has the 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. The members of this family are found mainly in certain bacteria and archaea.

Glycosyltransferase involved in cell wall bisynthesis [Cell wall/membrane/envelope biogenesis].

Glycosyl transferases group 1. Mutations in this domain of PIGA lead to disease (Paroxysmal Nocturnal haemoglobinuria). Members of this family transfer activated sugars to a variety of substrates, including glycogen, Fructose-6-phosphate and lipopolysaccharides. Members of this family transfer UDP, ADP, GDP or CMP linked sugars. The eukaryotic glycogen synthases may be distant members of this family.

UDP-Glc:1,2-diacylglycerol 3-a-glucosyltransferase and similar proteins. This family is most closely related to the GT1 family of glycosyltransferases. UDP-glucose-diacylglycerol glucosyltransferase (EC 2.4.1.337, UGDG; also known as 1,2-diacylglycerol 3-glucosyltransferase) catalyzes the transfer of glucose from UDP-glucose to 1,2-diacylglycerol forming 3-D-glucosyl-1,2-diacylglycerol.

glycosyltransferases MtfB, WbpX, and similar proteins. This family is most closely related to the GT4 family of glycosyltransferases. MtfB (mannosyltransferase B) in E. coli has been shown to direct the growth of the O9-specific polysaccharide chain. It transfers two mannoses into the position 3 of the previously synthesized polysaccharide.