IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
artículos
Título:
Functional reconstitution of the Mycobacterium tuberculosis long-chain acyl-CoA carboxylase from multiple acyl-CoA subunits
Autor/es:
GAGO, G.; DIACOVICH, L.; GRAMAJO, H; QUEMARD, A; GAGO, G.; DIACOVICH, L.; GRAMAJO, H; QUEMARD, A; BAZET LYONNET, B; BARDOU, F; BAZET LYONNET, B; BARDOU, F
Revista:
FEBS JOURNAL
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Lugar: Londres; Año: 2017 vol. 284 p. 1110 - 1125
ISSN:
1742-464X
Resumen:
Mycobacterium tuberculosis produces a large number of structurally diverselipids that have been implicated in the pathogenicity, persistence andantibiotic resistance of this organism. Most building blocks involved in thebiosynthesis of all these lipids are generated by acyl-CoA carboxylaseswhose subunit composition and physiological roles have not yet beenclearly established. Rather controversial data in the literature refer to theexact protein composition and substrate specificity of the enzyme complexthat produces the long-chain a-carboxy-acyl-CoAs, which are substratesinvolved in the last step of condensation mediated by the polyketide synthasePks13 to synthesize mature mycolic acids. Here we have successfullyreconstituted the so-called long-chain acyl-CoA carboxylase (LCC) complex from its purified components, the a subunit (AccA3), the e subunit(AccE5) and the two b subunits (AccD4 and AccD5), and demonstratedthat the four subunits are essential for its activity. Furthermore, we alsoshowed by substrate competition experiments and the use of a specific inhibitorthat the AccD5 subunit?s role in the carboxylation of the long acyl-CoAs, as part of the LCC complex, was structural rather than catalytic.Moreover, AccD5 was also able to carboxylate its natural substrates,acetyl-CoA and propionyl-CoA, in the context of the LCC enzyme complex.Thus, the supercomplex formed by these four subunits has the potentialto generate the main substrates, malonyl-CoA, methylmalonyl-CoAand a-carboxy-C24?26-CoA, used as condensing units for the biosynthesisof all the lipids present in this pathogen.