Chirality-Dependent Adsorption between Amphipathic Peptide and POPC Membrane

Area of Science:

• Molecular interactions
• Biophysics
• Chirality in molecular systems

Background:

• Chiral molecule-membrane interactions are vital for molecular science and medicine.
• Understanding how cell membranes selectively interact with chiral peptides is poorly understood at a microscopic level.

Purpose of the Study:

• To investigate the microscopic interactions between an amphipathic peptide (C6) and a POPC membrane.
• To characterize the kinetics and thermodynamics of peptide enantiomer adsorption to the membrane.
• To elucidate the mechanism behind chirality-dependent peptide-membrane interactions.

Main Methods:

• Direct molecular dynamics simulations to study peptide-membrane interactions.
• Umbrella sampling techniques to determine free energy landscapes and identify energy barriers.
• Analysis of local interactions, lipid distributions, and peptide helix rotation.

Main Results:

• Slower adsorption kinetics observed for peptides composed of D-amino acids.
• A significant free-energy barrier identified for D-amino acid peptides, correlating with kinetic data.
• Chirality-dependent differences in local interactions and lipid distributions around the peptide.
• Adsorption and helix rotation occur concurrently, with Trp residue conformation being a key factor.

Conclusions:

• The study provides a molecular-level understanding of how peptide chirality influences membrane interactions.
• Differences in adsorption are explained by Trp residue conformations and Trp-lipid interactions.
• Findings may guide the design of chiral-sensitive membrane systems.