Nucleotide sequence and initial functional characterization of the clcR gene encoding a LysR family activator of the clcABD chlorocatechol operon in Pseudomonas putida.
AUTOR(ES)
Coco, W M
RESUMO
The 3-chlorocatechol operon clcABD is central to the biodegradative pathway of 3-chlorobenzoate. The clcR regulatory gene, which activates the clcABD operon, was cloned from the region immediately upstream of the operon and was shown to complement an insertion mutation for growth on 3-chlorobenzoate. ClcR activated the clcA promoter, which controls expression of the clcABD operon, in trans by 14-fold in an in vivo promoter probe assay in Pseudomonas putida when cells were incubated with 15 mM 3-chlorobenzoic acid. Specific binding of ClcR to the clcR-clcA intergenic promoter region was observed in a gel shift assay. Nucleotide sequence analysis of the clcR gene predicts a polypeptide of 32.5 kDa, which was confirmed by using specific in vivo 35S labeling of the protein from a T7 promoter-controlled ATG fusion construct. ClcR shares high sequence identity with the LysR family of bacterial regulator proteins and has especially high homology to a subgroup of the family consisting of TcbR (57% amino acid sequence identity), TfdS, CatR, and CatM. ClcR was shown to autoregulate its own production in trans to 35% of unrepressed levels but partially relieved this autorepression under conditions that induced transcription at the clcA promoter. Several considerations indicate that the clcR-clcABD locus is most similar to the tcbR-tcbCDEF regulon.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=196156Documentos Relacionados
- Purification of the LysR family regulator, ClcR, and its interaction with the Pseudomonas putida clcABD chlorocatechol operon promoter.
- Nucleotide sequencing and characterization of Pseudomonas putida catR: a positive regulator of the catBC operon is a member of the LysR family.
- 2-chloromuconate and ClcR-mediated activation of the clcABD operon: in vitro transcriptional and DNase I footprint analyses.
- Partial nucleotide sequence of the chlorocatechol degradative operon tfdCDEF of pJP4 and similarity to promoters of the chlorinated aromatic degradative operons tfdA and clcABD.
- Interaction of two LysR-type regulatory proteins CatR and ClcR with heterologous promoters: functional and evolutionary implications.