Transcriptional regulation, nucleotide sequence, and localization of the promoter of the catBC operon in Pseudomonas putida

Abstract

The catB and catC genes encode cis,cis-muconate lactonizing enzyme I (EC 5.5.1.1) and muconolactone isomerase (EC 5.3.3.4), respectively. These enzymes are required for the dissimilation of benzoate to 13-ketoadipate by Pseudomonas putida and are under coordinate transcriptional regulation. By deletion analysis and the use of pKT240 as a promoter probe vector, we located a single promoter region for the catBC operon upstream of catB. RNA-DNA hybridization studies, together with reverse transcriptase mapping, demonstrated that this promoter must be activated in the presence of an inducer molecule for effective transcription of the operon. In addition, the transcription initiation site was located 64 base pairs upstream of the catB initiation codon, and sequences upstream of -43 were required for promoter function. The catBC promoter was compared with other positively regulated procaryotic promoters to identify possible consensus sequences.Pseudomonads and other soil microorganisms are able to utilize a variety of natural and synthetic compounds as sole sources of carbon. Their ability to dissimilate synthetic chlorinated compounds such as 3-chlorobenzoic acid, 2,4-dichlorophenoxyacetic acid, and 2,4,5-trichlorophenoxyacetic acid to nontoxic components (12) makes them attractive candidates for use in the environment to detoxify chemical wastes. Presently, there is no safe, economical means available for the removal of such hazardous chemicals. Having detailed information about the structural and regulatory genes involved in degradative processes increases the likelihood that organisms with these capabilities can be used for the purpose of chemical detoxification and gain approval for release into the environment.

Cloning and sequencing of two tandem genes involved in degradation of 2,3-dihydroxybiphenyl to benzoic acid in the polychlorinated biphenyl-degrading soil bacterium Pseudomonas sp. strain KKS102

“…4-n4- (2,26). By using unidirectional deletion mutants, it was shown that the gene coding for 23DBDO with only 58 bp upstream from the initiation codon ATG was expressed in P. putida (data not shown), suggesting that the promoterlike sequence located between other in nucleotide sequence.…”

Discontinuities in the evolution of Pseudomonas putida cat genes

“…Divergence of the cat regions within P. putida from the corresponding genes in Pseudomonas strain RB1 was indicated by the finding that cat genes from the latter organism were stably maintained on broad-host-range plasmids after their introduction into mutants derived from the P. putida biotype strain (1,2). To ascertain the extent to which cat genes from the P. putida biotype strain and from the Pseudomonas strain RB1 differ in nucleotide sequence, it was necessary to clone the cat region from the biotype strain.…”

Characterization of catechol catabolic genes from Rhodococcus erythropolis 1CP

“…For catechol catabolism, sequencing of the corresponding cat genes from several gram-negative strains has shown that isofunctional genes in these bacteria are clearly homologous (1,10,26,32,43,44,55). Similarly, the catechol 1,2-dioxygenase of Arthrobacter sp.…”