N-acetyl-alpha-D-glucosaminyl L-malate synthase BshA. Members of this protein family are BshA, a glycosyltransferase required for bacillithiol biosynthesis. This enzyme combines UDP-GlcNAc and L-malate to form N-acetyl-alpha-D-glucosaminyl L-malate synthase. Bacillithiol is a low-molecular-weight thiol, an analog of glutathione and mycothiol, and is found largely in the Firmicutes [Biosynthesis of cofactors, prosthetic groups, and carriers, Glutathione and analogs].

This family is most closely related to the GT1 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 mainly in bacteria, while some of them are also found in Archaea and eukaryotes.

Glycosyl transferase family 41. This family of glycosyltransferases includes O-linked beta-N-acetylglucosamine (O-GlcNAc) transferase, an enzyme which catalyzes the addition of O-GlcNAc to serine and threonine residues. In addition to its function as an O-GlcNAc transferase, human OGT, also appears to proteolytically cleave the epigenetic cell-cycle regulator HCF-1.

Predicted O-linked N-acetylglucosamine transferase, SPINDLY family [Posttranslational modification, protein turnover, chaperones]