glycosyltransferase family 4 proteins. This family is most closely related to the GT4 family of glycosyltransferases. 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 in certain bacteria and Archaea.

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.

Domain of unknown function (DUF1972). Members of this family of functionally uncharacterized domains are found in bacterial glycosyltransferases and rhamnosyltransferases.

glycosyltransferase family 1 and related proteins with GTB topology. 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.