Table 2.
Reversal potentials of Q117 mutants
| Ion X+ | WT ChR2 | Q117E | Q117R | Q117V | Q117Y |
|---|---|---|---|---|---|
| Li+ | −8.6 ± 0.5 (9) | −11.7 ± 0.7 (6) | −10.3 ± 0.7 (6) | −8.9 ± 0.5 (7) | −6.2 ± 0.7 (10) |
| Na+ | −9.4 ± 0.5 (11) | −25.8 ± 2.0 (19) | −10.5 ± 0.3 (7) | −10.0 ± 0.6 (7) | −9.4 ± 0.7 (13) |
| K+ | −14.8 ± 2.1 (14) | −27.8 ± 1.0 (8) | −28.6 ± 0.4 (5) | −22.5 ± 1.7 (13) | −12.2 ± 1.2 (21) |
| Rb+ | −29.3 ± 0.8 (5) | −35.8 ± 3.6 (6) | −27.7 ± 0.3 (5) | −29.6 ± 0.7 (5) | −24.7 ± 0.3 (10) |
| Cs+ | −28.4 ± 2.6 (5) | −35.3 ± 4.2 (6) | −29.9 ± 0.2 (5) | −29.7 ± 0.6 (8) | −27.6 ± 2.0 (8) |
Reversal potentials were determined by current-voltage relationships and 115 mM XCl in the external solution (pH = 9.0) on oocytes expressing WT ChR2, Q117E, Q117R, Q117V, and Q117Y. Mean values ± SE (n).