Purification and characterization of the diphtheria toxin repressor.

AUTOR(ES)

Schmitt, M P

RESUMO

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.

Documentos Relacionados

• Purification and characterization of nucleolin and its identification as a transcription repressor.
• Expression, purification, and functional characterization of the carboxyl-terminal domain fragment of bacteriophage 434 repressor.
• Characterization of mutations that inactivate the diphtheria toxin repressor gene (dtxR).
• Regulation of the acetate operon in Escherichia coli: purification and functional characterization of the IclR repressor.
• Metal stoichiometry and functional studies of the diphtheria toxin repressor