Stability constants K and half saturation constants KS for the cross-reaction of anthrax and C2 toxin.

bility constants K for the binding of C2I, EF or LF to PA63 or C2II channels reconstituted in lipid bilayer membranes. The membranes were formed from diphytanoyl phosphatidylcholine/n-decane. The aqueous phase contained 150 mM KCl, buffered to pH 5.5 to 6 using 10 mM MES-KOH; T = 20°C. Measurements were performed at a membrane potential of 20 mV. The data represent the means of at least three individual titration experiments. KS is the half saturation constant, i.e. 1/K. Some of the wild-type toxin combinations (given in bold) were taken from reference [20].