Western analysis using anti-FLAG M2 monoclonal antibody to assess ChpA protein levels. Lanes: 1, PAO1ΔchpA(pAL79); 2, PAO1ΔchpA(pAL79FLAG); 3, PAO1ΔchpA(pAL86FLAG); 4, PAO1ΔchpA(pAL87FLAG); 5, PAO1ΔchpA(pAL92FLAG). Bacterial samples were harvested from exponentially growing cultures 1 h after induction with 0.3 mM IPTG.