The T4 bacteriophage of E.coli protects its DNA via two glycosyltransferases which glucosylate 5-hydroxymethyl cytosines (5-HMC) using UDP-glucose. These two proteins are the retaining alpha-glucosyltransferase (AGT) and the inverting beta-glucosyltransferase (BGT). The proteins in this family are AGT. AGT adopts the GT-B fold and binds both the sugar donor and acceptor to the C-terminal domain. There is evidence for a role of AGT in the base-flipping mechanism and for its specific recognition of the acceptor base.
Jiyao W et al.(2023). "The conserved domain database in 2023.",