Table II.
Kinetics of C166 Mutants
| Open time τo | Short closed time, τC1 | Long closed time, τC2 | Percent C2 | Burst duration | Openings per burst | τC3 | Percent C3 | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ms | ms | ms | ms | ms | ||||||||||||
| Kir6.2ΔC26 | 0.79 ± 0.06 | 0.31 ± 0.03 | 12.6 ± 2.9 | 41.3 ± 8.0 | 2.4 ± 0.6 | 2.4 ± 0.3 | ||||||||||
| Kir6.2ΔC26-C166S | 1.66 ± 0.10 | 0.28 ± 0.02 | 11.8 ± 1.5 | 0.64 ± 0.03 | 260 ± 48 | 129 ± 20 | ||||||||||
| Kir6.2ΔC26-C166T | 1.36 ± 0.09 | 0.32 ± 0.07 | 10.5 ± 3.6 | 0.59 ± 0.05 | 222 ± 63 | 121 ± 41 | ||||||||||
| Kir6.2ΔC26-C166A | 2.06 ± 0.30 | 0.32 ± 0.04 | 18.1 ± 2.3 | 0.37 ± 0.05 | 363 ± 26 | 163 ± 22 | ||||||||||
| Kir6.2ΔC26-C166M | 1.27 ± 0.06 | 0.29 ± 0.03 | 16.0 ± 5.5 | 0.53 ± 0.12 | 258 ± 51 | 161 ± 25 | ||||||||||
| Kir6.2ΔC26-C166L | 1.31 ± 0.20 | 0.30 ± 0.02 | 2.6 ± 0.74 | 4.6 ± 0.33 | 44 ± 21 | 30 ± 19 | 17.1 ± 61.3 | 1.3 ± 0.6 | ||||||||
| Kir6.2ΔC26-C166V | 0.93 ± 0.06 | 0.30 ± 0.02 | 15.6 ± 11.7 | 44.5 ± 3.6 | 2.6 ± 0.6 | 2.3 ± 0.4 | ||||||||||
| Coexpressed with SUR1 | ||||||||||||||||
| Kir6.2 + SUR1 | 1.69 ± 0.11 | 0.33 ± 0.01 | 16.1 ± 6.6 | 18.0 ± 5.4 | 13.5 ± 4.4 | 7.1 ± 4.6 | ||||||||||
| Kir6.2ΔC26-C166 + SUR1 | 2.13 ± 0.05 | 0.30 ± 0.06 | 13.1 ± 6.1 | 0.09 ± 0.01 | 385 ± 23 | 154 ± 19 |
Kinetic parameters were measured at −60 mV. Three patches were analyzed in each case except for Kir6.2ΔC26/C166S, where n = 6.