title: Metalloregulatory DNA-binding protein encoded by the merR gene: isolation and characterization.
abstract: The MerR protein mediates the induction of the mercury resistance phenotype in bacteria; it has been isolated in order to study the effects of metal-ion induced changes in the metabolism of prokaryotic cells at the molecular level. After DNA sequences responsible for negative autoregulation were removed, the 16-kilodalton protein was overproduced and purified to more than 90 percent homogeneity by a salt extraction procedure that yields about 5 milligrams of protein per gram of cells. Complementation data, amino terminal analysis, gel filtration, and deoxyribonuclease I protection studies demonstrate that the purified merR gene product is a dimer under nondenaturing conditions and that it binds specifically to DNA, in the presence and absence of mercury, at a palindromic site which is directly between the -10 and -35 regions of the structural genes and adjacent to its own promoter. These initial results indicate that MerR is a DNA-binding metalloregulatory protein that plays a central role in this heavy metal responsive system and they delineate an operator site in the mer operon.
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification*; D001483:Base Sequence; D002850:Chromatography, Gel; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000302:isolation & purification*; D046911:Macromolecular Substances; D008628:Mercury; D009875:Operator Regions, Genetic; D011815:R Factors / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; C051124:MerR protein, Bacteria; D004247:DNA; D008628:Mercury