Molecular Dynamics Simulation Study on Interactions of Cycloviolacin with Different Phospholipids

Area of Science:

• Biochemistry
• Biophysics
• Computational Biology

Background:

• Cyclotides are stable, cyclic peptides from plants with diverse bioactivities.
• Their bioactivities often stem from interactions with lipid membranes.
• Understanding these interactions is key to developing cyclotide-based therapeutics.

Purpose of the Study:

• To investigate the molecular interactions of cycloviolacin O2 (cyO2) with different lipid bilayers.
• To elucidate the mechanism of cyO2 binding to membranes at a molecular level.
• To provide insights for designing cyclotide-based antibacterial agents.

Main Methods:

• Molecular dynamics simulations were employed.
• Interactions of cyO2 with three distinct lipid bilayers were simulated: POPE, POPG-doped POPE, and POPC.
• Binding affinities and interaction mechanisms were analyzed.

Main Results:

• Cycloviolacin O2 formed stable complexes with POPE-containing bilayers.
• cyO2 exhibited weak binding and surface diffusion on POPC bilayers.
• Electrostatic attraction drove initial binding, with POPE bilayers showing stronger interactions due to favorable head group and hydrophobic tail interactions.

Conclusions:

• Steric hindrance from POPC's methyl groups impedes cyO2 binding compared to POPE.
• The study clarifies cyO2's preferential binding to POPE-rich membranes.
• Findings support the development of cyclotide-based antibacterial agents targeting specific membrane compositions.