Concentration dependence of the impact of PC on the polymerization of SaFtsZ (A), BsFtsZ (B), EfFtsZ (C), and SpFtsZ (D), as determined by monitoring time-dependent changes in absorbance at 340 nm (A340) at 25 °C. The time-dependent A340 polymerization profiles are shown for each target FtsZ in the presence of DMSO vehicle (black) or PC at a concentration of 0.5 (red), 1.0 (blue), or 2.0 (orange) µg/mL. Experimental conditions for all the FtsZ polymerization studies were 5 µM protein, 50 mM Tris•HCl (pH 7.4), 50 mM KCl, and 10 mM magnesium acetate. Polymerization reactions were initiated by addition of 4 mM GTP at the times indicated by the arrows.