TABLE 3.
IVST and KD of WT and mutant channels in the presence of CssIVE15A
The voltage dependence of activation was measured as described under “Experimental Procedures.” IVST is the normalized voltage-sensor trapping current observed at a test pulse to −60 mV following a prepulse. For channels in which saturating effects of CssIVE15A could be recorded, KD values were calculated from fitting the data to the voltage sensor trapping model (supplemental Fig. S2). IVST data are presented as mean ± S.E.
| Channel | Concentration | IVST (−Pre) | IVST (+Pre) | n | KD |
|---|---|---|---|---|---|
| nm | nm | ||||
| WT | 500 | 0 | 11.9 ± 2.3% | 5 | 1130 |
| A841N | 500 | 0 | 2.8 ± 0.7% | 5 | NAa |
| 1000 | 0 | 5.3 ± 1.1% | 4 | ||
| L846A | 500 | 0 | 0.1 ± 0.3% | 4 | NA |
| 1000 | 0 | 0.1 ± 0.3% | 3 | ||
| N842R | 200 | 5.1 ± 0.7% | 26.0 ± 3.2% | 7 | NA |
| 500 | 9.0 ± 1.5% | 53.0 ± 4.5% | 6 | ||
| 1000 | 8.9 ± 0.9% | 55.0 ± 4.0% | 8 | ||
| V843A | 20 | 0 | 4.0 ± 1.0% | 4 | 263 |
| 50 | 0 | 10.4 ± 2.0% | 7 | ||
| 100 | 0 | 19.1 ± 3.5% | 5 | ||
| 200 | 0 | 29.9 ± 2.4% | 7 | ||
| 500 | 0 | 56.0 ± 5.0% | 5 | ||
| 1000 | 0 | 49.2 ± 3.9% | 5 | ||
| E844N | 20 | 0 | 2.9 ± 0.9% | 4 | 425 |
| 50 | 0 | 8.4 ± 1.9% | 3 | ||
| 200 | 0 | 26.3 ± 3.1% | 5 | ||
| 300 | 0 | 38.8 ± 13.7% | 3 | ||
| 400 | 0 | 50.3 ± 7.2% | 4 | ||
| 500 | 0 | 50.3 ± 6.5% | 5 |
a NA, not applicable.