부산대학교 도서관

Introduction: The Mce proteins are encoded in a variable number of operons (from one to eight) in all Mycobacterium species. A role in the transport of host and mycobacterial lipids has been demonstrated for some Mce proteins in the pathogen Mycobacterium tuberculosis but little is known about these proteins in Mycobacterium smegmatis, a soil dweller species. Objective: To investigate the role of Mce proteins in M. smegmatis. Method: We used a non-targeted GC-MS approach to define the metabolic profiles of knockout mutants in mce operons of M. smegmatis. Metabolomic analysis was complemented with thin layer chromatography and transcriptional studies. Result: We demonstrated that the lack of Mce4 proteins alters the primary carbon metabolism of M. smegmatis by reducing the content of fatty acids and increasing the accumulation of two stress-related compounds, glutamate/glutamine and triacyl glycerol (TAG). We also provide evidence supporting that the accumulation of TAG in a Δ mce4 mutant depends on the bacterial redox state. Conclusion: These results, together with the finding that the cell surface of the Δ mce4 mutant is significantly altered, support a role for Mce4 in maintaining the cell wall lipids architecture of M. smegmatis, which, when altered, induces a redox imbalance that results in the accumulation of the stress-related compounds. [ABSTRACT FROM AUTHOR]