Table 2.

Negative fixed charge density (molarity) of channels

Channel	100 mM KCl	250 mM KCl	Mean
WT (PA63)7	0.70	0.85	0.78
(PA63E302S)7	0.60	0.83	0.72
(PA63E343S)7	0.68	0.80	0.74
(PA63D276S)7	0.70	0.74	0.72
(PA63D335S)7	0.58	0.77	0.68
(PA63E308S)7	0.55	0.72	0.64
(PA63D315S)7	0.50	0.63	0.57
(PA63F427A)7	0.38	0.48	0.43

Negative fixed charge density (molarity) of channels (calculated from Eq. 1) with [KCl]_trans = 100 and 250 mM KCl. Each entry is the value of [N] that fits the data in Figs. 2 and 3.