mannosyltransferases of glycosyltransferase family 4 and similar proteins. This family is most closely related to the GT1 family of glycosyltransferases. ORF704 in E. coli has been shown to be involved in the biosynthesis of O-specific mannose homopolysaccharides.

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.

Bordetella parapertussis WlbH and similar proteins. This family is most closely related to the GT4 family of glycosyltransferases. Staphylococcus aureus CapJ may be involved in capsule polysaccharide biosynthesis. WlbH in Bordetella parapertussis has been shown to be required for the biosynthesis of a trisaccharide that, when attached to the B. pertussis lipopolysaccharide (LPS) core (band B), generates band A LPS.

Shigella dysenteriae WbnK and similar proteins. This family is most closely related to the GT4 family of glycosyltransferases. WbnK in Shigella dysenteriae has been shown to be involved in the type 7 O-antigen biosynthesis.

colanic acid biosynthesis glycosyltransferase WcaI.