The chlorocatechol 1,2-dioxygenase gene, designated as tcbC (J5-2) (GenBank Accession No. EF111021), was cloned from total DNA of Pseudomonas aeruginosa J5-2 which can degrade 1,2,4-trichlorobenzene. The deduced amino acid sequence analysis of tcbC (JS-2) shows that it is different from tcbC (P51) cloned from another 1,2,4-trichlorobenzene-degrader Pseudomonas sp. P51. tcbC (J5-2) is only 95% similar to tcbC (P51) at the amino acid level.Three critical amino acid residues in tcbC (J5-1) are Leu-48, Ala-52, and Ile-73. Otherwise, they are Val-48, Ala-52, and Met-73 in tcbC (P51). mRNA accumulation of tcbC in J5-2 was quantified by real-time reverse transcription-PCR, when J5-2 grew on 1,2-dichlorobenzene, 1,3-dichlorobensene and 1,2,4-trichlorobenzene respectively. The results show that 1,2, 4-trichlorobenzen is a better inducer than 1,2- and 1,3-dichlorobensene.
