Detection of multiple protein conformational ensembles in solution via deconvolution of charge-state distributions in ESI MS.

Monitoring the changes in charge-state distributions of protein ions in electrospray ionization (ESI) mass spectra has become one of the commonly accepted tools to detect large-scale conformational changes of proteins in solution. However, these experiments produce only qualitative, low-resolution information. Our goal is to develop a procedure that would produce quantitative data on protein conformational isomers coexisting in solution at equilibrium. To that end, we have examined the evolution of positive ion charge-state distributions in the