Teaching an old dog new tricks: new strategies for SAXS data analysis of proteins in solution

Full text: Small Angle X-Ray Scattering (SAXS) is a popular and well established experimental technique with an extensive range of applications. Such fact arises from its flexible sample preparation, allowing researchers to study proteins in the most diverse environments and experimental conditions. SAXS is of special interest to protein studies, and hybrid data analysis methods with inputs from other techniques, such as NMR spectroscopy and X-Ray crystallography, yield complimentary results, allowing better understanding of protein structure and dynamics in solution. In recent years, new SAXS data analysis methods for proteins are emerging with new ways to address model validation, structural parameters calculation and integration with databases. Some of these tools do not require an user input, allowing one to obtain immediately relevant information on the protein conformation in a way that it could be implemented for automated data analysis pipelines in beamlines. The aim of this study is to highlight recent advances in this field and illustrate its applicability and performance to data obtained in the SAXS1 beamline at LNLS. To do so, we measured chaperone proteins related to the Hsp70 and Hsp90 families, which are of special biological relevance due to its role in protein misfolding and aggregation issue. We have shown that the use of these new tools for SAXS data analysis can, undoubtedly, improve our understanding on molecular chaperone structure and dynamics. (author)