Analysis of two gene clusters involved in 2,4,6-trichlorophenol degradation by Ralstonia pickettii DTP0602.
Ralstonia pickettii DTP0602 utilizes 2,4,6-trichlorophenol (2,4,6-TCP) as sole source of carbon and energy. We have characterized hadABC which is involved in the degradation of 2,4,6-TCP. To identify the other genes involved in 2,4,6-TCP degradation, the DNA sequence around hadABC was determined. A regulatory gene, hadR, homologous to the LysR-type transcriptional regulator was located upstream of hadA, but no maleylacetate (MA) reductase gene was located near hadABC. An 8.4-kb DNA fragment containing a MA reductase gene, hadD, was cloned using a DNA probe designed from the N-terminal sequence of purified MA reductase. hadD was located upstream of an open reading frame, hadS, which codes for a homolog of the LysR-type transcriptional regulator. A hadS insertion mutant, DTP62S, constitutively expressed MA reductase when grown on aspartate in the absence of 2,4,6-TCP. MA reductase was repressed in DTP62S supplemented with hadS. HadR and HadS are proposed to be a positive and a negative regulator, respectively. A draft genome sequence analysis revealed that the hadRXABC and hadSYD clusters were separated by 146-kb on the 8.1-Mb chromosome.
Department of Biomedical Engineering, Faculty of Engineering, Okayama University of Science, Japan. thatta@bme.ous.ac.jp
Takashi
T
Hatta
Eiji
E
Fujii
Noboru
N
Takizawa
D001224:Aspartic Acid / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics*; D001673:Biodegradation, Environmental; D002733:Chlorophenols / Q000378:metabolism*; D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial; D003001:Cloning, Molecular; D015342:DNA Probes / Q000235:genetics; D004926:Escherichia coli; D015964:Gene Expression Regulation, Bacterial; D005810:Multigene Family; D016254:Mutagenesis, Insertional; D016366:Open Reading Frames; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000235:genetics; D010957:Plasmids; D049920:Ralstonia pickettii / Q000235:genetics*
D001426:Bacterial Proteins; D002733:Chlorophenols; D015342:DNA Probes; D001224:Aspartic Acid; D044925:Oxidoreductases Acting on CH-CH Group Donors; C021530:maleylacetate reductase; C024564:2,4,6-trichlorophenol