Table 1.
Deactivation time constants for HERG and mutant constructs in the absence and presence of 10 mM Mg2+
| 0 mM Mg2+ | 10 mM Mg2+ | n | Vtest | |
|---|---|---|---|---|
| WT (slow)** | 2567 ± 129 | 789 ± 82 | 11 | +40 mV |
| WT (fast)** | 480 ± 25 | 219 ± 21 | 11 | +40 mV |
| D456A (slow) | 201 ± 21 | 165 ± 10 | 6 | +40 mV |
| D456A (fast)** | 52 ± 2 | 39 ± 1 | 6 | +40 mV |
| D460A* | 99 ± 5 | 76 ± 3 | 8 | +40 mV |
| D466A* | 111 ± 5 | 84 ± 7 | 5 | +40 mV |
| D509A* | 47 ± 1 | 42 ± 1 | 8 | +40 mV |
| D456A/D460A (slow) | 163 ± 7 | 166 ± 9 | 8 | +60 mV |
| D456A/D460A (fast) | 24 ± 1 | 26 ± 2 | 8 | +60 mV |
| D456A/D509A | 63 ± 3 | 59 ± 3 | 7 | +60 mV |
| D460A/D509A* | 50 ± 2 | 44 ± 1 | 5 | +60 mV |
| D466A/D509A** | 76 ± 2 | 53 ± 2 | 11 | +60 mV |
Values for the deactivation time constants (in ms, mean ± SEM) were derived from single or double exponential fits to the tail currents (see Figs. 1A and 3B). The number of experiments, n, and the test pulse, Vtest, are indicated.
*
and ** denote significant differences in the presence and absence of 10 mM Mg2+ p < 0.001 and p < 0.05, respectively, using one-way ANOVA.