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Updated: Jun 17, 2026

Measurement of Total Calcium in Neurons by Electron Probe X-ray Microanalysis
Published on: November 20, 2013
SEC-SAXS and HDX-MS: A powerful combination. The case of the calcium-binding domain of a bacterial toxin
Darragh P O'Brien1, Sébastien Brier2, Daniel Ladant1
1Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, Paris, France.
Abstract:
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 monodispersity 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.
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