Table 2. The FRET (E) and Stoichiometry (S) of the FRET states of OpuA-K521C, their relative abundance and the transition rate constants between the states.
| Condition* | Low-FRET state (L) | High-FRET state (H) | Transition rate (s–1) | Number of FRET dwells | |||||
|---|---|---|---|---|---|---|---|---|---|
| S | E | % dwells | S | E | % dwells | L-H | H-L | ||
| 50 mM BIS-TRIS pH 7.0, 0 mM KCl | 0.537 | 0.250 | 64.1 | 0.521 | 0.749 | 35.9 | 118 | 153 | 16,788 |
| 0 mM KCl | 0.531 | 0.248 | 66.9 | 0.519 | 0.742 | 33.1 | 123 | 175 | 27,047 |
| 0 mM KCl, 100 µM glycine betaine | 0.532 | 0.245 | 68.3 | 0.517 | 0.781 | 31.7 | 120 | 166 | 17,364 |
| 50 mM KCl | 0.526 | 0.225 | 68.0 | 0.516 | 0.735 | 32.0 | 88 | 153 | 14,708 |
| 100 mM KCl | 0.525 | 0.202 | 74.6 | 0.513 | 0.691 | 25.4 | 78 | 178 | 13,532 |
| 200 mM KCl | 0.519 | 0.183 | 81.4 | 0.518 | 0.663 | 18.6 | 41 | 153 | 16,454 |
| 400 mM KCl | 0.516 | 0.168 | 82.0 | 0.518 | 0.620 | 18.0 | 28 | 120 | 15,946 |
| 600 mM KCl | 0.497 | 0.180 | 82.6 | 0.490 | 0.628 | 17.4 | 42 | 173 | 38,604 |
| 600 mM KCl (V149Q) | 0.495 | 0.164 | 81.9 | 0.492 | 0.608 | 18.1 | 31 | 112 | 11,034 |
| 1000 mM KCl | 0.505 | 0.148 | 79.9 | 0.511 | 0.591 | 20.1 | 26 | 109 | 12,666 |
| 600 mM KCl, 20 mM Mg-ATP | 0.524 | 0.157 | 81.5 | 0.527 | 0.510 | 18.5 | 16 | 121 | 12,061 |
| 600 mM KCl, 20 mM Mg-ATP, 100 µM glycine betaine | 0.515 | 0.155 | 78.5 | 0.511 | 0.507 | 21.5 | 0 | 52 | 17,155 |
| 600 mM KCl, 20 mM Mg-ATP, 100 µM glycine betaine (E190Q) | 0.540 | 0.141 | 81.4 | 0.547 | 0.505 | 18.6 | 7 | 38 | 10,832 |
| 600 mM KCl, 20 mM Mg-ATP, 100 µM glycine betaine, 500 µM orthovanadate | 0.517 | 0.154 | 78.9 | 0.513 | 0.529 | 21.5 | 17 | 87 | 21,052 |
| 600 mM KCl, 50 mM glutamate, 50 mM arginine | 0.510 | 0.162 | 79.9 | 0.513 | 0.549 | 20.1 | 19 | 133 | 12,722 |
All conditions, except the first, contained 50 mM HEPES-K pH 7.0.