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Updated: Jun 20, 2026
10:52
Gramicidin-based Fluorescence Assay; for Determining Small Molecules Potential for Modifying Lipid Bilayer Properties
Published on: October 13, 2010
Exploring ion permeation energetics in gramicidin A using polarizable charge equilibration force fields
Sandeep Patel1, Joseph E Davis, Brad A Bauer
1Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA. sapatel@udel.edu
Journal of the American Chemical Society
|October 1, 2009
Summary
Molecular dynamics simulations reveal that polarizable force fields accurately predict ion transport energy barriers in biological channels. This addresses previous overestimations and improves understanding of ion-protein interactions.
Area of Science:
- Biophysics
- Computational Biology
- Molecular Modeling
Background:
- All-atom molecular dynamics simulations are used to study ion transport in biological ion channels.
- Previous simulations with nonpolarizable force fields overestimated energy barriers, leading to inaccurate conductance predictions.
Purpose of the Study:
- To investigate ion permeation energetics in the gramicidin A channel using a novel polarizable force field.
- To assess the impact of polarization effects on ion-protein interactions in narrow biological channels.
Main Methods:
- All-atom molecular dynamics simulations.
- Utilized a novel polarizable force field for simulations.
- Calculated the potential of mean force for ion transport.
Main Results:
- The novel polarizable force field predicted a peak barrier height of 6 kcal/mol for ion permeation.
- This is significantly lower than the 12 kcal/mol barrier predicted by nonpolarizable force fields (e.g., GROMOS, CHARMM27).
- Nonpolarizable force fields do not account for electronic polarization effects.
Conclusions:
- Polarizable force fields offer more quantitative predictions of ion transport free energy surfaces.
- Results support the importance of polarization in accurately describing ion-protein interactions within biological channels.
- This study provides a more accurate model for ion channel function prediction.
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