Collision-Induced Unfolding Is Sensitive to the Polarity of Proteins and Protein Complexes
- 9 September 2019
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Society for Mass Spectrometry
- Vol. 30 (11), 2430-2437
- https://doi.org/10.1007/s13361-019-02326-z
Abstract
Collision-induced unfolding (CIU) uses ion mobility to probe the structures of ions of proteins and noncovalent complexes as a function of the extent of gas-phase activation prior to analysis. CIU can be sensitive to domain structures, isoform identities, and binding partners, which makes it appealing for many applications. Almost all previous applications of CIU have probed cations. Here, we evaluate the application of CIU to anions and compare the results for anions with those for cations. Towards that end, we developed a “similarity score” that we used to quantify the differences between the results of different CIU experiments and evaluate the significance of those differences relative to the variance of the underlying measurements. Many of the differences between anions and cations that were identified can be attributed to the lower absolute charge states of anions. For example, the extents of the increase in collision cross section over the full range of energies depended strongly on absolute charge state. However, over intermediate energies, there are significant difference between anions and cations with the same absolute charge state. Therefore, CIU is sensitive to the polarity of protein ions. Based on these results, we propose that the utility of CIU to differentiate similar proteins or noncovalent complexes may also depend on polarity. More generally, these results indicate that the relationship between the structures and dynamics of native-like cations and anions deserve further attention and that future studies may benefit from integrating results from ions of both polarities.Keywords
Funding Information
- National Science Foundation (CHE-1807382)
This publication has 50 references indexed in Scilit:
- Dissociation of Multisubunit Protein–Ligand Complexes in the Gas Phase. Evidence for Ligand MigrationJournal of the American Society for Mass Spectrometry, 2013
- Dissecting Heterogeneous Molecular Chaperone Complexes Using a Mass Spectrum Deconvolution ApproachCell Chemical Biology, 2012
- Bound Cations Significantly Stabilize the Structure of Multiprotein Complexes in the Gas PhaseAngewandte Chemie, 2012
- Quantifying Ligand Binding to Large Protein Complexes Using Electrospray Ionization Mass SpectrometryAnalytical Chemistry, 2012
- Bound Anions Differentially Stabilize Multiprotein Complexes in the Absence of Bulk SolventJournal of the American Chemical Society, 2011
- Enhancements in travelling wave ion mobility resolutionRapid Communications in Mass Spectrometry, 2011
- Combined Charged Residue-Field Emission Model of Macromolecular Electrospray IonizationAnalytical Chemistry, 2008
- High-resolution mass spectrometry of viral assemblies: Molecular composition and stability of dimorphic hepatitis B virus capsidsProceedings of the National Academy of Sciences of the United States of America, 2008
- Protein Complexes in the Gas Phase: Technology for Structural Genomics and ProteomicsChemical Reviews, 2007
- Origin of Asymmetric Charge Partitioning in the Dissociation of Gas-Phase Protein HomodimersJournal of the American Chemical Society, 2003