Fig. 4. Activation of σ^E upon expression of YaeL PDZ variants. Plasmids pKK11 (YaeL⁺-His₆-Myc), pTWV228 (vector), pKK131(YaeLΔPDZ-His₆-Myc), pKK135 [YaeLΔPDZ(D402N)-His₆-Myc] and pKK138 [YaeL(G214Q)-His₆-Myc] were introduced into TR71 [yaeL⁺ λ(rpoHP3-lacZ)]. Cells were grown in L medium containing 5 mM cAMP at 30°C, during which samples were withdrawn and assayed for β-galactosidase (LacZ) activity. Results were plotted against the turbidity of culture at each point.