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Updated: May 24, 2026
Realistic Membrane Modeling Using Complex Lipid Mixtures in Simulation Studies
Published on: September 1, 2023
Comparative molecular dynamics simulations of the antimicrobial peptide CM15 in model lipid bilayers
Yi Wang1, Diana E Schlamadinger, Judy E Kim
1Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA. yiwang@ucsd.edu
Abstract:
We report altogether 3-micros molecular dynamics (MD) simulations of the antimicrobial peptide CM15 to systematically investigate its interaction with two model lipid bilayers, pure POPC and mixed POPG:POPC (1:2). Starting with either an α-helical or a random-coil conformation, CM15 is found to insert into both bilayers. Peptide-lipid interaction is stronger with the anionic POPG:POPC than the zwitterionic POPC, which is largely attributed to the electrostatic attraction between CM15 and the negatively charged POPG. Simulations initiated with CM15 as a random coil allowed us to study peptide folding at the lipid-water interface. Interestingly, CM15 folding appears to be faster in POPC than POPG:POPC, which may be explained by a lower activation energy barrier of structural rearrangement in the former system. Our data also suggest that compared with the random-coil conformation, CM15 in a pre-folded α-helix has significantly reduced interactions with the lipids, indicating that peptide initial structures may bias the simulation results considerably on the 100-ns timescale. The implications of this result should be considered when preparing and interpreting future AMP simulations.
Insights
Antimicrobial peptide CM15 interacts with lipid bilayers, showing stronger binding to anionic POPG:POPC than zwitterionic POPC. Initial peptide structure significantly influences simulation outcomes on the 100-ns timescale.
Area of Science:
- Biophysics
- Computational Chemistry
- Membrane Biology
Background:
- Antimicrobial peptides (AMPs) are crucial in innate immunity.
- Understanding AMP-lipid interactions is key to developing new therapeutics.
- Molecular dynamics (MD) simulations offer insights into these complex interactions.
Purpose of the Study:
- To investigate the interaction of antimicrobial peptide CM15 with different model lipid bilayers.
- To explore the influence of initial peptide conformation on simulation results.
- To elucidate the role of electrostatic interactions in peptide-membrane binding.
Main Methods:
- 3-micros molecular dynamics (MD) simulations.
- Modeling of pure POPC and mixed POPG:POPC (1:2) lipid bilayers.
- Simulation of CM15 in both α-helical and random-coil conformations.
Main Results:
- CM15 inserts into both zwitterionic POPC and anionic POPG:POPC bilayers.
- Peptide-lipid interaction is stronger with POPG:POPC due to electrostatic attraction.
- CM15 folding is faster in POPC, potentially due to a lower energy barrier.
- Pre-folded α-helical CM15 shows reduced lipid interactions compared to random-coil.
Conclusions:
- Initial peptide structure significantly biases MD simulation results on the 100-ns timescale.
- Electrostatic interactions play a critical role in CM15 binding to anionic membranes.
- Careful consideration of initial conformations is necessary for accurate AMP simulation interpretation.
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