Purification and characterization of the diphtheria toxin repressor.
basic_science · Level V
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- Record sourced from PubMed, PMID 1502169.
- Also identified by PMC identifier 49753.
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Abstract
The diphtheria toxin repressor gene (dtxR) encodes a protein (DtxR) that regulates transcription of the diphtheria toxin gene (tox) by an iron-dependent mechanism. Cloned dtxR was expressed in Escherichia coli from the phage T7 gene 10 promoter, and DtxR was purified. Specific binding of DtxR to the tox+ operator was dependent on reduction of DtxR and the presence of ferrous ions. DtxR protected a sequence of approximately 30 nucleotide pairs, partially overlapping the tox promoter and containing a region of dyad symmetry, from digestion by DNase I. DtxR exhibited very little binding to the mutant tox-201 operator region and failed to bind to the promoter/operator region of the ferric uptake regulation (fur) gene of E. coli.
Medical subject headings
- Bacterial Proteins
- Corynebacterium diphtheriae
- DNA-Binding Proteins
- Diphtheria Toxin
- Escherichia coli
- Gene Expression Regulation, Bacterial
- Genes, Bacterial
- Genes, Regulator
- Operon
- Transcription, Genetic