TABLE 1.
Experimental and calculated interspin distances
Experimental interspin distances in the absence and in the presence of potassium were derived using DEERAnalysis2006 (36) and DipFit (37). Interspin distances of different KtrB models were calculated using the rotamer library approach (38). Models 3 and 4 are based on model 1 (see Fig. 8), taking into account the distances of columns 2 and 3, respectively.
| Experimental interspin distance r |
Calculated interspin distance r |
|||||
|---|---|---|---|---|---|---|
| −K+ | +K+ | Model 1 | Model 2 | Model 3 | Model 4 | |
| nm | nm | |||||
| Asp-222R1/Thr-318R1 | ≥1.8a | 1.4 ± 0.1 | 2.1 and 2.4 | 1.9 | 1.8 | 1.5 |
| Asp-222R1/Ser-327R1 | >1.8 | >1.8 | 1.5 | 0.9 and 1.25 | 1.7 | 1.5 and 2.0 |
| Met-311R1/Thr-318R1 | 3.5 ± 0.2 | 3.5 ± 0.2 | 2.3 | 2.0 | 2.9 and 3.7 | 3.0 |
| Thr-318R1/Val-331R1 | 1.5 ± 0.1 | 1.7 ± 0.2 | 2.4 and 2.9 | 2.9 | 3.2 | 1.7 |
| Ser-327R1/Val-331R1 | 1.1 ± 0.1 | 1.1 ± 0.1 | 0.8 | 1.8 | 1.0 | 0.6 and 1.0 |
a The fraction of the singly spin-labeled component is in the range of 30–50%.