Members of this family belong to glycosyltransferase family 9 [1]. Lipopolysaccharide is a major component of the outer leaflet of the outer membrane in Gram-negative bacteria. It is composed of three domains; lipid A, Core oligosaccharide and the O-antigen. All of these enzymes transfer heptose to the lipopolysaccharide core.

1: A classification of nucleotide-diphospho-sugar glycosyltransferases based on amino acid sequence similarities Campbell JA, Davies GJ, Bulone V, Henrissat B; Biochem J 1997;326:929-939. PMID:9334165

2: Enzymatic synthesis of lipopolysaccharide in Escherichia coli. Purification and properties of heptosyltransferase I. Kadrmas JL, Raetz CR; J Biol Chem 1998;273:2799-2807. PMID:9446588