title: Characterization of a response regulator protein that binds to Anabaena sp. strain L-31 kdp-promoter region.
abstract: The potassium dependent adenosine triphosphatase (Kdp-ATPase), encoded by the kdp operon, is a potassium uptake system found in several prokaryotes. The cyanobacterium Anabaena sp. strain L-31 shows the presence of two kdp operons (kdp1 and kdp2) of which the kdp2 is predominantly induced in response to potassium limitation or desiccation stress. Two ORFs, encoding a sensor kinase and a response regulator, respectively, were identified upstream of the kdp2 operon in Anabaena sp. strain L-31. The response regulator protein, tagged with 6 additional C-terminal histidine residues, was over-expressed in Escherichia coli and purified by affinity chromatography. Employing the protein-specific antiserum, the response regulator protein was detected in Anabaena L-31 cytosolic fractions. The response regulator protein bound to the kdp2 promoter region with higher affinity than kdp1 promoter region. Addition of acetyl phosphate increased the ability of the protein to bind to kdp2 promoter region by several fold, suggesting a phosphorylation-dependent binding of response regulator to the promoter. These data implicate the response regulator protein in regulation of kdp2 expression in Anabaena sp. strain L-31.
authors.affiliation: Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, Maharashtra 400085, India.
authors.forename: Anand
authors.initials: A
authors.lastname: Ballal
authors.forename: Shree Kumar
authors.initials: SK
authors.lastname: Apte
mesh_terms: D000595:Amino Acid Sequence; D017033:Anabaena / Q000235:genetics*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D024202:Electrophoretic Mobility Shift Assay; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers