Fluoranthene metabolism and associated proteins in Mycobacterium sp. JS14

Fluoranthene is a polycyclic aromatic hydrocarbon (PAH) commonly present in PAH‐contaminated soils. We studied fluoranthene catabolism and associated proteins in Mycobacterium sp. JS14, a bacterium isolated from a PAH‐contaminated soil in Hilo (HI, USA). Fluoranthene degrades in at least three separated pathways via 1‐indanone, 2′,3′‐dihydroxybiphenyl‐2,3,‐dicarboxylic acid, and naphthalene‐1,8‐dicarboxylic acid. Part of the diverse catabolism is converged into phthalate catabolism. An increased expression of 25 proteins related to fluoranthene catabolism is found with 1‐D PAGE or 2‐DE and nano‐LC‐MS/MS. Detection of fluoranthene catabolism associated proteins coincides well with its multiple degradation pathways that are mapped via metabolites identified. Among the up‐regulated proteins, PAH ring‐hydroxylating dioxygenase α‐subunit and β‐subunit and 2,3‐dihydroxybiphenyl 1,2‐dioxygenase are notably induced. The up‐regulation of trans‐2‐carboxybenzalpyruvate hydratase suggests that some of fluoranthene metabolites may be further degraded through aromatic dicarboxylic acid pathways. Catalase and superoxide dismutase were up‐regulated to control unexpected oxidative stress during the fluoranthene catabolism. The up‐regulation of chorismate synthase and nicotine‐nucleotide phosphorylase may be necessary for sustaining shikimate pathway and pyrimidine biosynthesis, respectively. A fluoranthene degradation pathway for Mycobacterium sp. JS14 was proposed and confirmed by proteomic study by identifying almost all the enzymes required during the initial steps of fluoranthene degradation.