Figure 3. Comparison of model-based and measured SAXS profiles.

The predicted scattering profile is based on an electron microscopy derived off-state tarantula HMM model. Integrated scattering intensity (I in arbitrary units) is given as a function of momentum transfer (q in Å⁻¹, approximately proportional to the scattering angle). The model used is PDB i.d. 3DTP, with the deletion of the 50 N-terminal residues of the RLC unique to this tarantula myosin. The fit of the PDB computed profile to the squid HMM EGTA profile is quite good (slight aggregation is noted at smallest q), and is much better than the fit to the squid HMM Ca2+ data.