Involved in the final steps of polyacyltrehalose (PAT) biosynthesis. Catalyzes the transfer of three mycolipenoyl groups onto diacyltrehalose (DAT) to form PAT. Activity is probably potentiated by the DAT/PAT transporter MmpL10. Inhibited by the lipase inhibitor tetrahydrolipstatin (THL). Mutant accumulates DAT in the cytoplasm and at the cell surface. Does not produce PAT. The topology of this protein is unsure. According to PubMed:25124040, the C-terminal catalytic site is on the periplasmic side of the inner membrane. However, PubMed:25331437 authors conclude that Chp2 has the opposite topology, and that the C-terminal catalytic site is on the cytoplasmic side of the membrane. Belongs to the mycobacterial PPE family.