Reaction: (1) 2 a mycocerosyl-[mycocerosic acid synthase] + a phthiocerol = a dimycocerosyl phthiocerol + 2 holo-[mycocerosic acid synthase]
(2) 2 a mycocerosyl-[mycocerosic acid synthase] + a phthiodiolone = a dimycocerosyl phthiodiolone + 2 holo-[mycocerosic acid synthase]
(3) 2 a mycocerosyl-[mycocerosic acid synthase] + a phenolphthiocerol = a dimycocerosyl phenolphthiocerol + 2 holo-[mycocerosic acid synthase]
Glossary: a mycocerosate = 2,4,6-trimethyl- and 2,4,6,8-tetramethyl-2-alkanoic acids present in many pathogenic mycobacteria. The chiral centers bearing the methyl groups have an L (levorotatory) stereo configuration.
a phthiocerol = a linear carbohydrate molecule to which one methoxyl group, one methyl group, and two secondary hydroxyl groups are attached.
a phthiodiolone = an intermediate in phthiocerol biosynthesis, containing an oxo group where phthiocerols contain a methoxyl group
a phenolphthiocerol = a compound related to phthiocerol that contains a phenol group at the ω end of the molecule
Other name(s): papA5 (gene name)
Systematic name: mycocerosyl-[mycocerosic acid synthase]:phenolphthiocerol/phthiocerol/phthiodiolone dimycocerosyl transferase
Comments: The enzyme, present in certain pathogenic species of mycobacteria, catalyses the transfer of mycocerosic acids to the two hydroxyl groups at the common lipid core of phthiocerol, phthiodiolone, and phenolphthiocerol, forming dimycocerosate esters. The fatty acid precursors of mycocerosic acids are activated by EC 188.8.131.52, long-chain fatty acid adenylyltransferase FadD28, which loads them onto EC 184.108.40.206, mycocerosate synthase. That enzyme extends the precursors to form mycocerosic acids that remain attached until transferred by EC 220.127.116.112.
Links to other databases: BRENDA, EXPASY, ExplorEnz, KEGG, MetaCyc, CAS registry number:
1. Onwueme, K.C., Ferreras, J.A., Buglino, J., Lima, C.D. and Quadri, L.E. Mycobacterial polyketide-associated proteins are acyltransferases: proof of principle with Mycobacterium tuberculosis PapA5. Proc. Natl Acad. Sci. USA 101 (2004) 4608-4613. [PMID: 15070765]
2. Buglino, J., Onwueme, K.C., Ferreras, J.A., Quadri, L.E. and Lima, C.D. Crystal structure of PapA5, a phthiocerol dimycocerosyl transferase from Mycobacterium tuberculosis. J. Biol. Chem 279 (2004) 30634-30642. [PMID: 15123643]
3. Chavadi, S.S., Onwueme, K.C., Edupuganti, U.R., Jerome, J., Chatterjee, D., Soll, C.E. and Quadri, L.E. The mycobacterial acyltransferase PapA5 is required for biosynthesis of cell wall-associated phenolic glycolipids. Microbiology 158 (2012) 1379-1387. [PMID: 22361940]
4. Touchette, M.H., Bommineni, G.R., Delle Bovi, R.J., Gadbery, J.E., Nicora, C.D., Shukla, A.K., Kyle, J.E., Metz, T.O., Martin, D.W., Sampson, N.S., Miller, W.T., Tonge, P.J. and Seeliger, J.C. Diacyltransferase activity and chain length specificity of Mycobacterium tuberculosis PapA5 in the synthesis of alkyl β-diol lipids. Biochemistry 54 (2015) 5457-5468. [PMID: 26271001]