This domain family is found in bacteria, and is typically between 179 and 190 amino acids in length. This family is the C terminal region of AftA. The enzyme catalyses the addition of the first key arabinofuranosyl residue from the sugar donor beta-D-arabinofuranosyl-1-monophosphoryldecaprenol to the galactan domain of the cell wall, thus priming the galactan for further elaboration by the arabinofuranosyltransferases. The C terminal region is predicted to be directed towards the periplasm.

1: Identification of a novel arabinofuranosyltransferase (AftA) involved in cell wall arabinan biosynthesis in Mycobacterium tuberculosis. Alderwick LJ, Seidel M, Sahm H, Besra GS, Eggeling L; J Biol Chem. 2006;281:15653-15661. PMID:16595677