Fig 4.
PelA catalytic mutation in PAO1 arrests colony morphology, biofilm formation, and Pel synthesis. PAO1ΔwspFΔpsl PBADpel and the catalytic mutant D528A in pelA were assessed for colony morphology in the presence of 0.5% arabinose (A) and microtiter dish biofilm formation in the presence and absence of the arabinose inducer (B). (C) Strains were probed for PelA, PelC, and RNA polymerase (RNAp) protein expression by Western blotting and Pel polysaccharide by dot blotting. The asterisk indicates the PelA protein. The bottom panel represents an anti-Pel blot of these strains. (D) To verify the Pel antisera, Pel polysaccharide dot blots were analyzed for PAO1ΔwspF, PAO1ΔwspFΔpel, PAO1ΔwspFΔpsl, and PAO1ΔwspFΔpelΔpsl.