Implicit vs. Explicit Solvent Models for Calculating X-ray Solution Scattering Curves

Theoretical calculation of X-ray solution scattering curves of proteins in the solution phase is strongly influenced by solvent contributions in the form of solvent-excluded volume and hydration layer that are generally represented either implicitly or explicitly. To investigate the effect of the implicit and explicit solvent models on the calculated scattering curves, we developed a new program, X-ray Solution Scattering (XSoS) based on implicit (XSoS-implicit) and explicit (XSoS-explicit) solvent models. Both XSoS-implicit and XSoS-explicit can calculate X-ray solution scattering curves with high accuracy. Overall, the implicit solvent model has practical advantages over the explicit solvent model for the analysis of experimental X-ray solution scattering data.