Table 1.
Properties of S3–S4 linker deletion mutants
| Mutant | Amino acids remaining in deletion zone | τact (0)* (ms) | τdeact (0) (ms) | V1/2† (mV) | zδ† | N |
|---|---|---|---|---|---|---|
| ShakerΔ | VVAEEEDTLNLPKAPV | |||||
| SPQDKSSNQAMSLAI | 3.2 ± 0.8 | 12.1 ± 1.3 | −52 ± 9 | 1.9 ± 0.9 | 5 | |
| C-terminal side of the deleted region | ||||||
| ShakerΔΔ(330–360) | None | 141.0 ± 6.1 | 96.7 ± 11.7 | −28 ± 3 | 0.9 ± 0.1 | 10 |
| ShakerΔΔ(330–359) | I | 535.1 ± 9.2 | — | −7 ± 1 | 0.8 ± 0.1 | 6 |
| ShakerΔΔ(330–358) | AI | 692.1 ± 107.0 | 22.7 ± 8.2 | −46 ± 11 | 2.1 ± 0.9 | 5 |
| ShakerΔΔ(330–357) | LAI | 5.7 ± 0.1 | 161.6 ± 15.4 | −41 ± 9 | 1.6 ± 0.9 | 5 |
| ShakerΔΔ(330–356) | SLAI | 89.1 ± 2.1 | 8.3 ± 1.1 | 7 ± 2 | 1.7 ± 0.7 | 5 |
| ShakerΔΔ(330–355) | MSLAI | 458.9 ± 9.8 | 80.9 ± 10.7 | −23 ± 5 | 1.7 ± 1.0 | 7 |
| ShakerΔΔ(330–354) | AMSLAI | 13.2 ± 1.9 | 29.5 ± 8.9 | −39 ± 9 | 2.8 ± 1.0 | 10 |
| ShakerΔΔ(330–353) | QAMSLAI | 6.4 ± 0.5 | 120.0 ± 48.4 | −25 ± 7 | 2.8 ± 1.1 | 6 |
| ShakerΔΔ(330–352) | NQAMSLAI | 7.5 ± 2.5 | 42.0 ± 6.6 | −23 ± 7 | 4.2 ± 1.1 | 5 |
| ShakerΔΔ(330–350) | SSNQAMSLAI | 4.5 ± 0.3 | 49.6 ± 6.9 | −46 ± 8 | 2.3 ± 0.8 | 10 |
| N-terminal side of the deleted region | ||||||
| ShakerΔΔ(331–360) | V | 23.8 ± 0.3 | 76.2 ± 7.8 | 38 ± 10 | 2.9 ± 1.0 | 5 |
| ShakerΔΔ(332–360) | VV | 3.3 ± 0.2 | 13.1 ± 0.9 | −40 ± 8 | 1.4 ± 0.9 | 5 |
| ShakerΔΔ(333–360) | VVA | 22.9 ± 8.0 | 220.0 ± 66.3 | −77 ± 7 | 3.4 ± 1.0 | 6 |
| Other deletion mutants | ||||||
| ShakerΔΔ(332–357) | VVLAI | 44.1 ± 1.2 | — | 46 ± 7 | 1.2 ± 0.2 | 5 |
| ShakerΔΔ(330–355) | MSLVV | 1,484.0 ± 311.1 | — | −2 ± 1 | 1.2 ± 0.2 | 5 |
| A359VI360V | ||||||
| ShakerΔΔ(332–355) | VVMSLAI | 13.4 ± 1.4 | — | −42 ± 5 | 2.6 ± 0.5 | 5 |
ShakerΔ is the control channel ShakerH4Δ(6–46).
*
The activation time constant at zero voltage was obtained by simple interpolation of the τact vs. voltage data in those cases that measurements of τact could be done for positive and negative voltages or by extrapolation of the data to 0 mV when the τact data were only obtained for positive voltages (solid lines in Fig. 2A).
†
Parameters calculated by fitting the voltage activation data to Eq. 5. N is the number of different cell-attached patches used to measure macroscopic currents induced by ShakerΔ and S3–S4 linker mutants.