title: The histidine kinase CusS senses silver ions through direct binding by its sensor domain.
abstract: The Cus system of Escherichia coli aids in protection of cells from high concentrations of Ag(I) and Cu(I). The histidine kinase CusS of the CusRS two-component system functions as a Ag(I)/Cu(I)-responsive sensor kinase and is essential for induction of the genes encoding the CusCFBA efflux pump. In this study, we have examined the molecular features of the sensor domain of CusS in order to understand how a metal-responsive histidine kinase senses specific metal ions. We find that the predicted periplasmic sensor domain of CusS directly interacts with Ag(I) ions and undergoes a conformational change upon metal binding. Metal binding also enhances the tendency of the domain to dimerize. These findings suggest a model for activation of the histidine kinase through metal binding events in the periplasmic sensor domain.
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA.
authors.forename: Swapna A
authors.initials: SA
authors.lastname: Gudipaty
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA; Department of Soil, Water and Environmental Sciences, University of Arizona, Tucson, AZ 85721, USA. Electronic address: mcevoy@email.arizona.edu.
authors.forename: Megan M
authors.initials: MM
authors.lastname: McEvoy
mesh_terms: D002414:Cations, Monovalent; D003300:Copper / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D000071677:Histidine Kinase; D007700:Kinetics; D019897:Periplasm / Q000201:enzymology* / Q000235:genetics; D011485:Protein Binding; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012834:Silver / Q000378:metabolism*
chemical_list: D002414:Cations, Monovalent; D029968:Escherichia coli Proteins; D012834:Silver; D003300:Copper; D011494:Protein Kinases; D000071677:Histidine Kinase
keywords: Copper; Cus system; CusS; Histidine kinase; Silver; Two-component system