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Updated: May 20, 2026

Analyzing Protein Architectures and Protein-Ligand Complexes by Integrative Structural Mass Spectrometry
Published on: October 15, 2018
Detection and characterization of large-scale protein conformational transitions in solution using charge-state
Rinat R Abzalimov1, Agya K Frimpong, Igor A Kaltashov
1Department of Chemistry, University of Massachusetts-Amherst, Amherst, MA, USA.
Abstract:
Ion charge-state distribution analysis in electro-spray ionization mass spectrometry (ESI-MS) is a robust and fast technique for direct detection and characterization of coexisting protein conformations in solution. Compact folded proteins give rise to ESI-generated ions carrying a relatively small number of charges, whereas less compact conformers accommodate upon ESI a larger number of charges depending on the extent of their unfolding. A chemometric approach [1] based upon factor analysis is applied to determine contributions from individual conformers to the overall CSD. Here we present basic guidelines for the use of this MS-based technique: from the preparation of suitable solutions for ESI-MS to the acquisition of reliable MS data and their subsequent analysis.
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