Genes Involved in the Benzoate Catabolic Pathway in PHEA-2

A putative gene encoding a LysR-type regulator located upstream from the gene was found in PHEA-2. Disruption of or destroyed the ability of PHEA-2 to utilize benzoate. The mutant was used to construct a genomic library for isolation of the complete gene cluster responsible for benzoate degradation. Sequence analysis showed that the cluster has three putative operons: , and . Unlike many well-characterized benzoate-degrading bacteria, muconate is unable to induce transcription of the PHEA-2 cluster. Reverse transcriptase-polymerase chain reaction (RT-PCR) results showed that the operon is activated by the BenM protein in the presence of benzoate. Moreover, a gel-retardation assay demonstrated that BenM binds to the promotor region of the gene. The activities of catechol 1,2-dioxygenase (C12O) and catechol 2,3-dioxygenase (C23O) showed that PHEA-2 converted benzoate to catechol for further degradation, possibly via an -cleavage pathway.