(A) Size exclusion chromatogram of RpfFBc–RpfRCt(FI). Fractions between the vertical lines were analyzed by 15% SDS-PAGE (inset). The positions of molecular weight standards are indicated above the trace. (B) Conformation sensitive gel electrophoresis of RpfFBc thioesterase activity in the presence and absence of RpfRCt(FI). The substrate was C12:0–ACP. Average percent conversion of substrate and standard deviation from three separate experiments is shown beneath each lane. The gel shown is a representative example of the three experiments. The numerical values underlying panel B can be found in S1 Data. ACP, acyl carrier protein; C12:0, dodecanoic acid; FI, RpfF, interaction; RpfF, regulation of pathogenicity factor F; RpfR, regulation of pathogenicity factor R.