Degradation of benzotrifluoride via the dioxygenase pathway in <i>Rhodococcus</i> sp. 065240

We previously isolated <i>Rhodococcus</i> sp. 065240, which catalyzes the defluorination of benzotrifluoride (BTF). In order to investigate the mechanism of this degradation of BTF, we performed proteomic analysis of cells grown with or without BTF. Three proteins, which resemble dioxygenase pathway enzymes responsible for isopropylbenzene degradation from <i>Rhodococcus erythropolis</i> BD2, were induced by BTF. Genomic PCR and DNA sequence analysis revealed that the <i>Rhodococcus</i> sp. 065240 carries the gene cluster, <i>btf</i>, which is highly homologous to the <i>ipb</i> gene cluster from <i>R. erythropolis</i> BD2. A mutant strain, which could not catalyze BTF defluorination, was isolated from 065240 strain by UV mutagenesis. The mutant strain had one mutation in the <i>btfT</i> gene, which encodes a response regulator of the two component system. The defluorinating ability of the mutant strain was recovered by complementation of <i>btfT</i>. These results suggest that the <i>btf</i> gene cluster is responsible for degradation of BTF.