Cross-validation of data in SAXS and cryo-EM

Cryo-Electron Microscopy (EM) and Small Angle X-ray Scattering (SAXS) are two different data acquisition modalities often used to glean information about the structure of large biomolecular complexes in their native states. A SAXS experiment is generally considered fast and easy but unveiling the structure at very low resolution, whereas a cryo-EM experiment needs more extensive preparation and post-acquisition computation to yield a 3D density map at higher resolution. In certain applications, one may need to verify if the data acquired in the SAXS and cryo-EM experiments correspond to the same structure (e.g., prior to reconstructing the 3D density map in EM). In this paper, a simple and fast method is proposed to verify the compatibility of the SAXS and EM experiments. The method is based on averaging the 2D correlation of EM images and the Abel transform of the SAXS data. The results are verified on simulations of conformational states of large biomolecular complexes.