Molecular Dynamics and Small-Angle X-ray Scattering: Comparison of Computational and Experimental Approaches to Studying Structures of Biological Complexes

The results of investigation of DNA-protein complexes by two independent structural methods, namely, molecular dynamics (MD) and small-angle X-ray scattering (SAXS), were compared. Molecular dynamics is a computational method enabling the visualization of the behavior of macromolecules in real media, which is based on the laws of physics, but it is limited by numerous simplifications. Small-angle X-ray scattering is an X-ray method, which allows the reconstruction of the three-dimensional structure of a system in solution from a one-dimensional small-angle scattering profile, but it faces the problem of ambiguity in solving inverse problems. The use of structural characteristics of the complexes determined by SAXS for the validation of 3D structural models generated by MD simulations made it possible to significantly reduce the ambivalence of theoretical predictions and demonstrated the efficiency of a combination of MD simulations and SAXS for solving problems of structural biology.