Figure 4.

Binding of Ba²⁺ to KcsA. Panel A illustrates Ba²⁺ binding to KcsA channels, monitored through the Ba²⁺ concentration dependence of the t_m of thermal denaturation. The results are the average (n = 3) t_m (in Celsius) ± SD. The symbols and colors are the same as in Figure 2. Panel B shows the fitting of the experimental data from Panel A to Equation (1) (see Methods). The apparent K_D values for the above binding events are given in Table 1.