. 2013 Mar 19;104(6):1230–1237. doi: 10.1016/j.bpj.2013.02.013

Table 3.

Permeability ratios P_X/P_Na of monovalent cations for Q117 mutants

Ion X⁺	WT ChR2	C34A/C36A	Q117E	Q117R	Q117V	Q117Y
Li⁺	1.03 (9)	1.07 (5)	0.91 (6)	0.96 (6)	1.02 (7)	1.13 (10)
Na⁺	1.00 (11)	0.97 (8)	0.52 (19)	0.95 (7)	0.98 (7)	1.00 (13)
K⁺	0.81 (14)	0.77 (7)	0.48 (8)	0.47 (5)	0.59 (13)	0.89 (21)
Rb⁺	0.45 (5)	0.50 (5)	0.35 (6)	0.48 (5)	0.45 (5)	0.54 (10)
Cs⁺	0.47 (5)	0.45 (5)	0.36 (6)	0.44 (5)	0.45 (8)	0.49 (8)

Permeability ratios determined as described in Materials and Methods. [X⁺] = 115 mM, pH = 9. Mean values ± SE of the mean (number of experiments).