Figure 7.

PqsE interacts with RhlR and increases RhlR sensitivity to C4-HSL. (a) Bioluminescence output from E. coli carrying rhlR, rhlA-luxCDABE, and the designated pqsE alleles on the pACYC184 plasmid in response to 200 nM C4-HSL, normalized to the OD₆₀₀ of the cultures. The “-” symbol designates the strain carrying the empty pACYC184 vector. The results shown are the average of two biological replicates performed in duplicate. Error bars represent standard deviations. ns = not significant, ****P < 0.0001, ***P < 0.0005 in one-way ANOVA compared to WT. (b) SDS-PAGE analysis of input (I) and elution (E) samples from PqsE–RhlR pull-down assays. 6xHis-PqsE was immobilized on Ni resin and exposed to lysate containing RhlR. On the gel, 6xHis-PqsE appears as a ∼34 kDa band and RhlR-mBTL as a ∼28 kDa band.