FIGURE 2.

Bile salts (DC) stimulate ToxR PPIs in a ToxS dependent manner. PPIs of ToxR with or without co‐expressed ToxS were tested in dependence of bile salts in E. coli W3110 ∆cyaA using BACTH (Karimova et al., 1998). See experimental procedures for details. The leucine zipper of the yeast GCN4 protein (zip) was used as a positive complementation control (+), while the empty plasmids pKT25 and pUT18C served as negative controls (‐). Cells were grown in LB supplemented with 0.05 mM IPTG to the stationary phase in the absence or presence of 0.1% DC (sodium deoxycholate). The functional complementation of the controls (black bars) and ToxR with or without ToxS (white bars) was quantified by measuring β‐galactosidase activities. DC treated samples are indicated by lined bars. The values are means of three biological replicates, each with technical triplicates with error bars, which represent the standard deviation. The controls contain five values each. Interactions are reported as Miller Units. The asterisks indicate significantly different means with p < .05 using Student's t‐test