Phosphoprotein gel stain of purified KdpFABC separated by SDS-PAGE, indicating the phosphorylation state of KdpB. The corresponding Coomassie stain shows the total protein amount loaded per lane. Phosphoprotein stains were quantified with ImageJ and normalized to the quantification of the Coomassie stain to correct for differing protein amounts, following which the phosphorylation by WT KdpD was set to 100%. Bars indicate the mean and error bars denote the standard deviation from biological triplicates (n = 3). Full phosphoprotein and Coomassie stains are shown in Supplementary Fig. 4.
