Component of a biotin-dependent acyl-CoA carboxylase complex. This subunit transfers the CO2 from carboxybiotin to the CoA ester substrate. The biotin-dependent acyl-CoA carboxylase complex is composed of an AccA protein, which contains the biotin carboxylase (BC) and biotin carboxyl carrier protein (BCCP) domains, and an AccD protein, which contains the carboxyl transferase (CT) domain. Does not show significant changes in expression throughout M.tuberculosis growth phases. Not essential for growth. Was identified as a high-confidence drug target. Belongs to the AccD/PCCB family.