Figure 3.

Response sensitivity of major and minor receptors. (A) Dose-response curves for cells that were pre-adapted to an ambient concentration of the respective ligand around the peak of the dynamic range (shown in brackets). Kinase activity is plotted as a function of final ligand concentration, normalized to the respective ambient concentration. (B) Response sensitivity at the peak of the dynamic range, S_R^P, for WT and otherwise wild-type cells each expressing a plasmid-encoded periplasmic binding protein (BP) at maximum induction of 10 μM salicylate. See text for the definition of S_R^P. (C) Native expression levels of receptors in wild-type cells normalized to Tsr, determined by immunoblot as described in Materials and methods and in Supplementary Figure S4. (D) S_R^P values from (B) normalized to the receptor fraction. Error bars indicate standard errors.