FIG 4.

The EPS Pel binds to CdrA. (A and B) Simultaneous overexpression of cdrAB and pel results in aggregation in liquid culture. (B) Data are means from three replicates, and error bars indicate standard deviations. (C) CdrA was detected in the eluant following a coimmunoprecipitation when both Psl and CdrA were present in culture supernatants and when both Pel and CdrA were present in culture supernatants. (D) Anti-CdrA Western blot analysis shows that both Psl and Pel, but not cellulose, chitosan, or starch, protect CdrA from degradation by P. aeruginosa supernatant (sup) proteases. Intact secreted CdrA, that is, CdrA not treated (−) with supernatant, is detected at approximately 150 kDa. The negative controls, boiled supernatant (lane B) and ΔlasB supernatant (lane Δ), do not proteolyze CdrA.