Table 2.
Axial tilt angles of labeled helices with respect to actin in the absence of nucleotide
| Labeling site | Model-based θAH (°) | Initial (θNH = 74.2°, ϕNH = −73.8°) | Optimized (θNH = 74.9°, ϕNH = −61.2°) | ||
| Experimental θAH (°) | Difference (°) | Experimental θAH (°) | Difference (°) | ||
| Relay helix (apo) | 84.4 | 74.8 ± 1.8 | −9.5 ± 1.8 | 83.4 ± 1.8 | −1.0 ± 1.8 |
| Helix K (U50) | 29.6 | 42.3 ± 1.9 | 12.7 ± 1.9 | 30.6 ± 1.9 | 0.9 ± 1.9 |
| Helix W (L50) | 77.5 | 83.5 ± 2.1 | 6.0 ± 2.1 | 78.4 ± 2.1 | 1.0 ± 2.1 |
Values are derived using probe orientations obtained either from EPR (Experimental columns) or directly from a cryo-EM model of actomyosin (Model-based column) (32).