Parameters for slow inactivation kinetics of Nav1.5 N405 channel mutants
Slow inactivation was measured as described in Figure 2. Data were fit with Boltzmann distribution to derive the voltage half-points of activation and inactivation (V½) and slope factors (dx) and the steady state value of availability (S2) (as described in Figure 2). The fraction of channels slow inactivated was determined from 1 - S2. The uncharged substitutions (Ala, Cys, Phe) were made in the Nav1.5 background (WT), whereas the charged substitutions (Asp, Glu, Arg, Lys) were performed in the Nav1.5 C373Y (WT-C373Y) channel. n values are given in the figure legends.
Slow Inactivation | Fraction | |||||
|---|---|---|---|---|---|---|
| Channel | V½ | dx | Available S2 | Slow Inactivated (1 - S2) | ||
| mV | ||||||
| WT | −86.5 ± 5.6 | 13.8 ± 5.1 | 0.39 ± 0.05 | 0.61 | ||
| WT-C373Y | −82.7 ± 0.01 | 12.6 ± 0.01 | 0.53 ± 0.001 | 0.47 | ||
| N406A | −90.7 ± 0.2 | 4.7 ± 0.8 | 0.06 ± 0.01 | 0.94 | ||
| N406C | −107.0 ± 4.1 | 13.3 ± 2.8 | 0.11 ± 0.02 | 0.89 | ||
| N406F | −109.4 ± 7.6 | 6.1 ± 5.0 | 0.18 ± 0.01 | 0.82 | ||
| N406D | −67.4 ± 6.7 | 13.4 ± 5.8 | 0.58 ± 0.04 | 0.42 | ||
| N406E | −90.2 ± 2.0 | 3.7 ± 1.7 | 0.31 ± 0.02 | 0.69 | ||
| N406R | −76.4 ± 1.5 | 9.4 ± 1.2 | 0.80 ± 0.01 | 0.20 | ||
| N406K | −86.2 ± 3.9 | 3.1 ± 2.3 | 0.80 ± 0.02 | 0.20 | ||