Glycosyltransferase, GT2 family [Carbohydrate transport and metabolism].

RfbF is a putative dTDP-rhamnosyl transferase. Shigella flexneri RfbF protein is a putative dTDP-rhamnosyl transferase. dTDP rhamnosyl transferases of Shigella flexneri add rhamnose sugars to N-acetyl-glucosamine in the O-antigen tetrasaccharide repeat. Lipopolysaccharide O antigens are important virulence determinants for many bacteria. The variations of sugar composition, the sequence of the sugars and the linkages in the O antigen provide structural diversity of the O antigen.

Glycosyltransferase family A (GT-A) includes diverse families of glycosyl transferases with a common GT-A type structural fold. Glycosyltransferases (GTs) are enzymes that synthesize oligosaccharides, polysaccharides, and glycoconjugates by transferring the sugar moiety from an activated nucleotide-sugar donor to an acceptor molecule, which may be a growing oligosaccharide, a lipid, or a protein. Based on the stereochemistry of the donor and acceptor molecules, GTs are classified as either retaining or inverting enzymes. To date, all GT structures adopt one of two possible folds, termed GT-A fold and GT-B fold. This hierarchy includes diverse families of glycosyl transferases with a common GT-A type structural fold, which has two tightly associated beta/alpha/beta domains that tend to form a continuous central sheet of at least eight beta-strands. The majority of the proteins in this superfamily are Glycosyltransferase family 2 (GT-2) proteins. But it also includes families GT-43, GT-6, GT-8, GT13 and GT-7; which are evolutionarily related to GT-2 and share structure similarities.