Concentration Effects in Peptide-Lipid Bilayer Interactions: A Coarse-Grained Molecular Dynamics Study

Area of Science:

• Biophysics
• Computational Biology
• Materials Science

Background:

• Peptide-lipid interactions are crucial for membrane function and disruption.
• Models exist to predict peptide-induced pore formation in lipid bilayers.
• Understanding these interactions is key to developing new antimicrobial and therapeutic agents.

Purpose of the Study:

• To test the predictions of Huang's two-state model for peptide-induced pore formation.
• To investigate the effects of peptide concentration on peptide-lipid bilayer interactions.
• To compare the membrane interaction mechanisms of antimicrobial and amyloidogenic peptides.

Main Methods:

• Martini 2 and Martini 3 molecular dynamics simulations.
• Simulations of melittin and amyloid-beta (Aβ(29-42)) peptide fragments.
• Analysis of peptide-lipid interactions and membrane properties at varying peptide concentrations.

Main Results:

• Peptides adsorb to the membrane interface and form transmembrane clusters beyond a critical peptide-to-lipid ratio.
• Cooperative peptide insertion did not correlate with a change in membrane thinning rate, differing from Huang's model predictions.
• Melittin and Aβ(29-42) exhibited similar peptide-lipid interaction characteristics.

Conclusions:

• Huang's model may not fully capture the complexities of peptide-lipid interactions, particularly the influence of peptide concentration on bilayer mechanics.
• Antimicrobial and amyloidogenic peptides likely employ similar mechanisms to disrupt lipid membranes.
• This finding supports a unified view of peptide-membrane interactions across different peptide types.