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 (By similarity). 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 Lipid metabolism; mycolic acid biosynthesis. Homodimer. Belongs to the CFA/CMAS family.