Table 1. Equilibrium affinity... | Rockefeller University Press

Table 1.

Equilibrium affinity measurements obtained for ion binding to KcsA and MthK K⁺ channels

Channel	Ion binding event	$K_{D}^{K^{+}}$	$K_{D}^{{Na}^{+}}$	n	Selectivity
		µM	µM
KcsA		80 ± 2	60,000 ± 800	1.3 ± 0.02	750
MthK	First	10 ± 3	2,000 ± 200	2.0 ± 0.2	200
MthK	Second	80 ± 10	9,000 ± 6,000	2.2 ± 0.5	110

Channel	Ion binding event	$K_{D}^{K^{+}}$	$K_{D}^{{Na}^{+}}$	n	Selectivity
		µM	µM
KcsA		80 ± 2	60,000 ± 800	1.3 ± 0.02	750
MthK	First	10 ± 3	2,000 ± 200	2.0 ± 0.2	200
MthK	Second	80 ± 10	9,000 ± 6,000	2.2 ± 0.5	110

$K_{D}^{K^{+}}$ and $K_{D}^{{Na}^{+}}$ are obtained from fitting the data in Figs. 3 and 5 to the ion competition model described in Materials and methods. The selectivity is $K_{D}^{{Na}^{+}} / K_{D}^{K^{+}}$ .

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