Mycofactocin is associated with ethanol metabolism in Mycobacteria

ABSTRACT: Mycobacterium tuberculosis (Mtb) assimilates cholesterol during chronic infection, and its in vitro growth in presence of cholesterol requires Mycofactocin (MFT) biosynthesis genes, although the basis of this requirement is unclear. MFT belongs to the class of ribosomally synthesized and post-translationally modified peptides conserved in many Actinobacteria, and its biological function and structure requires further confirmation. To identify the function of MFT, we characterized mft gene deletion mutants constructed in M. smegmatis, M. marinum and Mtb. We found that the growth deficit of mft deletion mutants in cholesterol – a phenotypic basis for gene essentiality prediction – is ethanol-dependent. Furthermore, functionality of MFT was strictly required for mycobacterial growth in ethanol, implicating its role in ethanol metabolism. Although ethanol is a poor growth substrate, it perturbed the cellular metabolism profoundly. Transcriptional analysis revealed that the disruption of MFT caused respiration dysfunction and associated redox imbalance, which is proposed as an underlying mechanism of growth retardation of MFT mutants in cholesterol. Finally, MSMEG_6242 was found to be indispensable for ethanol assimilation and is a candidate catalytic interactor with MFT. The function of MFT appears to resemble pyrroloquinoline quinone cofactor, similar to their biosynthetic steps. While our results serve as a salutary reminder that gene essentiality is dependent on a context in which it is probed, they also establish MFT as a redox cofactor, along with flavin or nicotinamide, to enable the function of its dependent enzymes in mycobacteria.

ORGANISM(S): Mycolicibacterium smegmatis Mycobacterium tuberculosis H37Rv Mycobacterium tuberculosis variant bovis

PROVIDER: GSE121398 | GEO | 2019/04/25

REPOSITORIES: GEO