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Production of Disulfide-stabilized Transmembrane Peptide Complexes for Structural Studies
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Multiple solution structures of the disordered peptide indolicidin from IMS-MS analysis.
Neelam Khanal1, Maissa M Gaye1, David E Clemmer1
1Department of Chemistry, Indiana University, Bloomington, IN 47405, United States.
International Journal of Mass Spectrometry
|March 26, 2019
Summary
The study reveals that the disordered peptide indolicidin adopts multiple distinct structures in various solutions. These conformations, identified using electrospray ionization coupled to ion mobility spectrometry-mass spectrometry (ESI-IMS-MS), change with solvent environment.
Area of Science:
- Biophysical Chemistry
- Structural Biology
- Mass Spectrometry
Background:
- Disordered peptides lack a stable three-dimensional structure in solution.
- Understanding peptide conformation is crucial for elucidating biological function and designing therapeutic agents.
Purpose of the Study:
- To investigate the solution-favored conformations of the 13-residue disordered peptide indolicidin.
- To explore how different solvent environments influence peptide structural populations.
Main Methods:
- Electrospray ionization coupled to ion mobility spectrometry-mass spectrometry (ESI-IMS-MS) was employed to analyze indolicidin.
- Collisional activation of isolated gas-phase conformations was performed using IMS-IMS-MS.
- Simulated annealing studies were conducted to explore conformational landscapes.
Main Results:
- ESI-IMS-MS revealed the coexistence of three distinct structural populations for indolicidin across various aqueous and non-aqueous solutions.
- Conformer types and their relative abundances were observed to vary significantly with changes in the solution environment.
- Gas-phase conformers were found to reflect the solution populations present in different solvent systems.
Conclusions:
- The study demonstrates that indolicidin exists as an ensemble of structures in solution, with the specific conformations being sensitive to the surrounding solvent.
- The findings suggest that gas-phase structures obtained via ESI-IMS-MS can provide valuable insights into solution-phase peptide behavior.
- Proline configuration appears to play a significant role in the emergence of multiple conformations in indolicidin.
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