SEC-SAXS and HDX-MS: A powerful combination. The case of the calcium-binding domain of a bacterial toxin

Small-angle X-ray Scattering (SAXS) is a relatively simple experimental technique that provides information on the global conformation of macromolecules in solution, be they fully structured, partially, or extensively unfolded. Size Exclusion chromatography in line with a SAXS measuring cell considerably improves the mono-dispersity and ideality of solutions, the two main requirements of a “good” SAXS sample. Hydrogen/Deuterium eXchange monitored by Mass Spectrometry (HDX-MS) offers a wealth of information regarding the solvent accessibility at the local (peptide) level. It constitutes a sensitive probe of local flexibility and, more generally, of structural dynamics. The combination of both approaches presented here is very powerful, as illustrated by the case of RD, a calcium binding protein that is part of a bacterial virulence factor. This article is protected by copyright. All rights reserved