Two practical Java software tools for small-angle X-ray scattering analysis of biomolecules

Small-angle X-ray scattering has established itself as a common technique in structural biology research. Here, two novel Java applications to aid modelling of three-dimensional macromolecular structures based on small-angle scattering data are described. MolScat is an application that computes small-angle scattering intensities from user-provided three-dimensional models. The program can fit the theoretical scattering intensities to experimental X-ray scattering data. SAFIR is a program for interactive rigid-body modelling into low-resolution shapes restored from small-angle scattering data. The program has been designed with an emphasis on ease of use and intuitive handling. An embedded version of MolScat is used to enable quick evaluation of the fit between the model and experimental scattering data. SAFIR also provides options to refine macromolecular complexes with optional user-specified restraints against scattering data by means of a Monte Carlo approach.