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Updated: Mar 2, 2026
07:33
Analyzing Protein Architectures and Protein-Ligand Complexes by Integrative Structural Mass Spectrometry
Published on: October 15, 2018
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Investigating the Structural Compaction of Biomolecules Upon Transition to the Gas-Phase Using ESI-TWIMS-MS
Paul W A Devine1, Henry C Fisher1, Antonio N Calabrese1
1Astbury Center for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK.
Summary
Collision cross-section measurements reveal that proteins and RNAs can collapse in the gas phase, deviating from predicted structures. Caution is advised when using collision cross-section data for structural modeling of non-globular biomolecules.
Area of Science:
- Biophysical chemistry
- Structural biology
- Analytical chemistry
Background:
- Collision cross-section (CCS) measurements from ion mobility spectrometry-mass spectrometry (IMS-MS) offer insights into biomolecule size and shape.
- Concerns exist regarding the maintenance of native-like conformations for proteins, especially those with dynamic regions, during gas-phase analysis.
Purpose of the Study:
- To investigate the gas-phase behavior of non-globular proteins and RNAs using CCS measurements.
- To assess the accuracy of predicted CCS values based on existing structural data.
- To evaluate the susceptibility of different biomolecules to gas-phase compaction.
Main Methods:
- Traveling wave ion mobility spectrometry-mass spectrometry (TW-IMS-MS) was employed to measure CCS values.
- A range of non-globular proteins and RNAs with varying sequences, sizes, and stabilities were analyzed.
- Measured CCS values were compared with predicted CCS values derived from available structural models.
Main Results:
- Measured CCS values for the studied proteins significantly deviated from predicted values, indicating gas-phase collapse.
- The extent of collapse varied depending on the protein's elongated structure.
- Two RNAs of similar mass but different solution structures exhibited gas-phase compaction, suggesting susceptibility.
Conclusions:
- Proteins and RNAs with non-globular folds may undergo significant structural changes (collapse) upon transitioning into the gas phase.
- Current structural models may not accurately predict the gas-phase behavior of these biomolecules.
- Caution is necessary when interpreting CCS data for structural modeling of proteins and RNAs, particularly those with dynamic or extended structures.
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