Requires Mn2+ or Mg2+. Isolated from Mycobacterium smegmatis [1] and Mycobacterium tuberculosis [2]. The enzyme catalyses the addition of a rhamnosyl unit to N-acetyl-¦Á-D-glucosaminyl-diphospho-trans,octacis-decaprenol, completing the synthesis of the linkage unit that attaches the arabinogalactan moiety to the peptidoglycan moiety in Mycobacterial cell wall.