Back to Search
Start Over
Identification of critical amino-terminal regions of XylS. The positive regulator encoded by the TOL plasmid.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 1992 Nov 15; Vol. 267 (32), pp. 22897-901. - Publication Year :
- 1992
-
Abstract
- The XylS protein is the positive regulator of the promoter controlling the meta-cleavage pathway (Pm) for catabolism of certain alkylbenzoates on the TOL plasmid of Pseudomonas. Transcription from Pm is mediated by XylS either in the presence of benzoate effectors or through XylS hyperproduction. Two regions of the NH2 terminus of XylS (residues 37-45) had been predicted to be involved in effector control of XylS transcriptional activation. Different methods were used to induce mutations in this region, including genetic selections (where Pm controlled a tetracycline resistance gene), bisulfite mutagenesis at a unique restriction site, and extensive oligonucleotide mutagenesis at residues 41 and 45. The mutants fell into four classes based on their phenotypes with respect to effector-mediated activation of a Pm-lacZ fusion: (a) effector profiles similar to wild type, (b) no Pm stimulation with benzoates, (c) altered effector specificity, and (d) higher basal Pm activities, in some cases including changes in effector specificity. In some mutants, higher basal Pm activity was apparently due to mutations that increased XylS stability. Substitutions at Arg-41 resulted in all four mutant phenotypes, indicating that this is a critical residue in XylS for effector stimulation of transcription activity.
- Subjects :
- Alleles
Amino Acid Sequence
Base Sequence
Codon genetics
DNA, Bacterial genetics
DNA, Bacterial isolation & purification
Mutagenesis
Point Mutation
beta-Galactosidase genetics
beta-Galactosidase metabolism
Escherichia coli genetics
Genes, Bacterial
Genes, Regulator
Plasmids
Promoter Regions, Genetic
Pseudomonas genetics
Trans-Activators genetics
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 267
- Issue :
- 32
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 1429638