TABLE I.
Electrophysiological Properties of KCNE3 Truncation Mutants
| τdeactivation (ms) | ||||||
|---|---|---|---|---|---|---|
| Construct | V1/2 (mV) | z | Basal Activation, A2 | fast | slow | |
| Q1 | −23.8 ± 0.6 | 1.39 ± 0.03 | 0.03 ± 0.01 | 221 ± 10 | ||
| E3 | 23.5 ± 2.5 | 0.75 ± 0.03 | 0.31 ± 0.02 | 14.9 ± 0.3 | 124 ± 5 | |
| Δ5-40 | 25.3 ± 5.1 | 0.81 ± 0.07 | 0.35 ± 0.03 | 19.1 ± 1.2 | 130 ± 5 | |
| Δ10-51 | 24.6 ± 5.5 | 1.00 ± 0.05 | 0.30 ± 0.02 | 14.4 ± 0.6 | 102 ± 4 | |
| Δ41-55 | 86.4 ± 7.4 | 0.51 ± 0.01 | 0.12 ± 0.01 | 10.9 ± 0.2 | 115 ± 3 | |
| Δ84 | 10.1 ± 1.3 | 0.67 ± 0.02 | 0.07 ± 0.01 | ND | ND | |
| Δ10-51/Δ84 | −10.0 ± 0.7 | 1.31 ± 0.05 | 0.14 ± 0.02 | ND | ND | |
| D90N | 27.8 ± 4.1 | 0.59 ± 0.02 | 0.28 ± 0.02 | 13.7 ± 0.4 | 156 ± 28 | |
| E1/E3 TM D76N | 4.5 ± 4.3 | 0.82 ± 0.03 | 0.08 ± 0.01 | ND | ND | |
Data from individual activation curves and deactivation time constants in KD98, obtained from four to six oocytes. Activation curves were fit to a Boltzmann function as described in materials and methods. Values are mean ± SEM. Basal activation (A2) for all activation curves was determined by normalizing the data after the Boltzmann fit such that the maximal current fitting parameter (A1) was equal to 1. V1/2 is the voltage of half-maximal activation and z is the slope factor. Time constants of deactivation were fit to a single or double exponential as described in materials and methods. ND, not determined.