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Updated: Jul 24, 2025
08:40
Using a Cyclic Ion Mobility Spectrometer for Tandem Ion Mobility Experiments
Published on: January 20, 2022
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Resolving Hidden Solution Conformations of Hemoglobin Using IMS-IMS on a Cyclic Instrument.
Edie M Sharon1, Lucas W Henderson1, David E Clemmer1
1Department of Chemistry, Indiana University Bloomington, Bloomington, Indiana 47405, United States.
Summary
Ion mobility spectrometry-mass spectrometry (IMS-MS) reveals complex hemoglobin structures. IMS-IMS and variable temperature ESI uncover hidden conformers, improving analysis of heterogeneous systems.
Area of Science:
- Analytical Chemistry
- Biophysical Chemistry
- Structural Biology
Background:
- Hemoglobin tetramer (Hb) exhibits complex structural heterogeneity.
- Ion mobility spectrometry-mass spectrometry (IMS-MS) is a powerful tool for analyzing biomolecular structures.
- Understanding protein conformational dynamics is crucial in various biological processes.
Purpose of the Study:
- To investigate the heterogeneous structural distributions of hemoglobin tetramer (Hb) in specific charge states using IMS-MS.
- To explore the utility of sequential IMS-IMS experiments for resolving closely related conformers.
- To examine the influence of solution temperature on Hb conformations using variable temperature ESI (vT-ESI) coupled with IMS-IMS.
Main Methods:
- Cyclic ion mobility spectrometry-mass spectrometry (IMS-MS) was employed.
- Sequential IMS-IMS experiments were performed by isolating and re-injecting drift time distributions.
- Variable temperature electrospray ionization (vT-ESI) was integrated to study temperature-dependent structural changes.
Main Results:
- IMS-MS data showed peak broadening for Hb charge states, suggesting the presence of multiple structures with similar cross-sections.
- IMS-IMS experiments demonstrated further separation of selected drift time regions, confirming the presence of distinct, closely related conformations.
- vT-ESI combined with IMS-IMS revealed temperature-dependent structural changes, with some features differing from single IMS analysis, highlighting the ability to discern obscured conformers.
Conclusions:
- Sequential IMS-IMS analysis effectively resolves complex conformer distributions obscured in single IMS experiments.
- The combination of vT-ESI and IMS-IMS provides a powerful approach to explore conformer distributions and stabilities in structurally heterogeneous systems.
- This methodology enhances the understanding of protein structural dynamics and heterogeneity.
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