Functional reconstitution of the Mycobacterium tuberculosis long-chain acyl-CoA carboxylase from multiple acyl-CoA subunits.

BAZET LYONNET B, DIACOVICH L, GAGO G, SPINA L, BARDOU F, LEMASSU A, QUÉMARD A, GRAMAJO H

FEBS JOURNAL

WILEY-BLACKWELL PUBLISHING, INC

Año: 2018

1742-464X

Mycobacterium tuberculosis produces a large number of structurally diverse lipids thathave been implicated in the pathogenicity, persistence and antibiotic resistance of thisorganism. Most building blocks involved in the biosynthesis of all these lipids aregenerated by acyl-CoA carboxylases (ACCase) whose subunit composition andphysiological roles have not yet been clearly established. A rather controversial data inthe literature refers to the exact protein composition and substrate specificity of theenzyme complex that produces the long-chain α-carboxy-acyl-CoAs; one of thesubstrates involved in the last step of condensation mediated by the polyketidesynthase Pks13 to synthesize mature mycolic acids. Here we have successfullyreconstituted the so called long-chain acyl-CoA carboxylase complex (LCC) from itspurified components: the α-subunit AccA3, the ε-subunit AccE5 and the two β-subunitsAccD4 and AccD5, and demonstrated that the four subunits are essential for its LCCactivity. Furthermore, we also showed by substrate competition experiments and theuse of a specific inhibitor of the AccD5 subunit, that its role in the carboxylation of thelong acyl-CoAs, as part of the LCC complex, was structural rather than catalytic.