Reconstruction of low-resolution three-dimensional density maps from one-dimensional small-angle X-ray solution scattering data for biomolecules

A Monte Carlo type reconstruction algorithm (Saxs3D) to yield low-resolution three-dimensional structures from one-dimensional small-angle X-ray scattering data (SAXS) is presented. It is demonstrated that Saxs3D reliably reproduces the shape of several test protein structures, with their respective SAXS profiles calculated theoretically from their known high-resolution atomic coordinate sets. A reconstruction for experimentally obtained scattering data for GroEL, a molecular chaperone, correctly reproduced the gross structural features of GroEL. Compared to other reconstruction methods described in the literature, Saxs3D has the advantage of allowing for any topology of the target structure, does not require any prior estimation of its dimensions, is fast and conceptually very simple.