FIGURE 6.

Extracellular complementation assay of ΔcodY cells with synthetic PapR peptides. ΔcodY and ΔpapR cell cultures were split at the entry of stationary phase and synthetic peptides were added when indicated at a final concentration of 5 μM. The cells harbor the pPplcA’-Z plasmid, carrying a transcriptional fusion between the promoter of plcA and lacZ. Cells were grown in LB at 37°C. Samples were collected for β-galactosidase assay 2.5 h after addition of the peptides. The sequence of the PapR peptides is indicated in Section “Materials and Methods.” The results are the mean values of two independent experiments, and the error bars represent standard deviation.