Table 2.
Voltage-dependence of wild-type and mutant channels
| Activation
|
Inactivation
|
|||
|---|---|---|---|---|
| Vmid, mV | Slope, mV | Vmid, mV | Slope, mV | |
| Wild type | 8.4 ± 0.7 | 6.7 ± 0.3 | −1.8 ± 1.6 | 12.0 ± 0.5 |
| P215L | 7.1 ± 2.0 | 9.1 ± 0.2 | −7.7 ± 3.5 | 13.5 ± 0.3 |
| P976L | 17.8 ± 0.8 | 7.4 ± 0.6 | 0.0 ± 1.5 | 11.9 ± 0.9 |
| P215L-P976L | 18.0 ± 0.8 | 10.6 ± 0.2 | 1.2 ± 3.0 | 14.4 ± 0.3 |
| I598P | 0.5 ± 1.1 | 6.3 ± 0.2 | −13.4 ± 2.4 | 9.1 ± 0.9 |
| L1306P | 5.6 ± 1.0 | 8.5 ± 0.4 | −2.0 ± 1.1 | 7.0 ± 0.6 |
| I598P-L1307P | −2.0 ± 0.8 | 8.3 ± 0.1 | −25.1 ± 0.8 | 9.8 ± 0.7 |
Current-voltage relationships or current-prepulse voltage relationships were fitted to Boltzmann distributions to derive values for the midpoint (Vmid) and the slope (mV/e-fold change in G/Gmax) of the curves for steady-state activation and steady-state inactivation. The prepulses were 5,000 ms long. Data represent means ± standard error obtained from 7–14 (activation) and 4–9 (inactivation) measurements. Underlining indicates statistically significant differences from values for the wild type, with P < 0.05.