Evidence of curvature bias and local POPG recruitment during surface-bound interactions of a cationic peptide with POPC/POPG membrane.

Antimicrobial peptides (AMPs) constitute an important class of antibacterial molecules whose mechanisms of action remain incompletely understood. Among the different stages of peptide-membrane interaction, membrane curvature has been recognized as a key physicochemical event associated with antimicrobial activity. Understanding how this curvature emerges during the early stages of peptide binding is therefore of considerable biological interest. In the present work, coarse-grained molecular dynamics simulations were used to investigate the curvature generated by the cationic peptide Magainin-2 during its surface-bound interaction with an anionic POPC:POPG (3:1) membrane. The results indicate a reproducible bias toward negative membrane curvature that Magainin-2 promotes while remaining in the surface-bound state. Simulations performed in the absence of peptide showed no comparable curvature bias. In peptide-containing systems, modest but consistent POPG recruitment was observed in the regions associated with membrane bending, suggesting a coupling between electrostatic lipid recruitment and local curvature bias. These findings provide computational evidence of membrane organization perturbation in surface-bound peptide interactions, before peptide insertion, contributing to the understanding of the early biophysical events involved in antimicrobial peptide activity.