TABLE 3.
Rates of E2(2Rb) → E1Na and E1 → E2(2Rb) conformational changes
Fitted rate constants for the traces in Figs. 5 and 6 are given. Rate constants of E2(2Rb) → E1Na for wild type and Asp369 represent averages from several independent experiments. The data for E2(2K) → E1Na are from a separate experiment and that for E1 → E2(2K) are derived from Fig. 7.
| Conformational change | Wild type | D369N | D369A |
|---|---|---|---|
| k s−1 ± S.E. | k s−1 ± S.E. | k s−1 ± S.E. | |
| E2(2Rb) → E1Na | 0.544 ± 0.087(n = 5) | 0.026 ± 0.005(n = 2) | 0.039 ± 0.001 s−1 |
| E1 → E2(2Rb) | |||
| 20 mm Rb+ | 5.1 ± 0.02 s−1 | 3.7 ± 0.01 s−1 | |
| 30 mm Rb+ | 13.5 ± 0.5 s−1 | 8.8 ± 0.15 s−1 | 8.4 ± 0.1 s−1 |
| 83 mm Rb+, Exp. 1 | 33.8 ± 0.6 s−1 | 28.2 ± 0.5 s−1 | 37 ± 0.7 s−1 |
| 83 mm Rb+, Exp. 2 | 28.9 ± 0.15 s−1 | 27.4 ± 0.2 s−1 | |
| E2(2K) → E1Na | 3.3 ± 0.03 s−1 | ||
| E1 → E2(2K) | 125 ± 15 s−1 | ||
| Extrapolated maximum value | |||