The enzyme is involved in the biosynthesis of dTDP-3-acetamido-3,6-dideoxy-¦Á-D-galactose. Four moieties of ¦Á-D-rhamnose and two moities of 3-acetamido-3,6-dideoxy-¦Á-D-galactose form the repeating unit of the glycan chain in the S-layer of the bacterium?Aneurinibacillus thermoaerophilus.