Catalyzes the formation of trans cyclopropanated ketomycolate or methoxymycolate through the conversion of a double bond to a cyclopropane ring at the proximal position of an oxygenated mycolic acid via the transfer of a methylene group from S-adenosyl-L-methionine. In the absence of MmaA2, CmaA2 has a non-specific cis-cyclopropanating activity and is able to catalyze the conversion of a double bond to a cis cyclopropane ring at the distal position of an alpha mycolic acid. Cyclopropanated mycolic acids are key factors participating in cell envelope permeability, host immunomodulation and persistence. 1-acyl-2-(9Z)-enoyl-sn-glycero-3-phospholipid + S-adenosyl-L-methionine = 1-acyl-2-(9-cyclopronane)-acyl-sn-glycero-3-phospholipid + H(+) + S-adenosyl-L-homocysteine Inhibited by S-adenosyl-N-decyl-aminoethyl (SADAE) and thiacetazone (TAC). Lipid metabolism; mycolic acid biosynthesis. Homodimer. Inactivation of cmaA2 causes accumulation of unsaturated derivatives of both the methoxy- and ketomycolates. The mycolic acids of the cmaA2 mutant lack trans-cyclopropane rings but are otherwise intact with respect to cyclopropane and methyl branch content. Deletion of cmaA2 has no effect on bacterial loads during mouse infection but causes hypervirulence due to an excessive immune activation which produces more-severe granulomatous pathology than wild-type, and increases both the macrophage activation and the macrophage inflammatory response. Was identified as a high-confidence drug target. Belongs to the CFA/CMAS family. Extended N-terminus.