Dimerization is essential for dna binding and repression of the trans-acting metalloregulatory arsr protein of i;suiieri'fiia uoli
Article
Xu, C, Rosen, BP. (1997). Dimerization is essential for dna binding and repression of the trans-acting metalloregulatory arsr protein of i;suiieri'fiia uoli
. FASEB JOURNAL, 11(9),
Xu, C, Rosen, BP. (1997). Dimerization is essential for dna binding and repression of the trans-acting metalloregulatory arsr protein of i;suiieri'fiia uoli
. FASEB JOURNAL, 11(9),
The plasmid-encoded arsenical resistance tars) operon of plasmid R773 produces resistance to trivalenl and pentavalent salts of the metalloids arsenic and antimony in cells of k/scheri'hia colt. The first gene in the operon, arsR. was previously shown to encode a homodimeric trans-acting metalloregulatory represser protein. 1)imerization of ArsR was investigated using lhe yeast two-hybrid system in which the ArsR protein was fused to the Saccharomyces ceret'isiae GAlA I)NA-binding doulain and GALl activation domain to produce chimeric proteins. Transcriptional activation of lacZ reporter indicated that dimerization of the ArsR is stable in yeast. The results indicated lhat residues 1-8 arm 90-117 are not required for ArsR dimerization. The genes for a series of truncated ArsR proteins containing six-histidine tags were constructed, and the proteins purilied. The mass of each recombinant protein, as determined by size exclusion chromatography, was consistent with the results from two-hybrid system. The results of 3-galactosidase assays in rive and gel mobility shift assays ir ritzy showed that dimers retained the ability to bind to the ars promoter and to response to inducer, while monomeric ArsRs did neither. These results suggest 1hat a :)re sequence of aboul SO residues has all of 0he information necessary for dimerization, repression and metal recognition.
