Abstract

The formation of transient pores in biological membranes is a critical process in cellular function and a key mechanism of action for many antimicrobial peptides. This study investigates the role of ordered lipid domain boundaries in regulating the membrane-disrupting activity of amphipathic peptides, specifically focusing on the probability of pore formation. Using a combination of coarse-grained molecular dynamics simulations and model membrane systems, we examined the partitioning and alignment of amphipathic peptides at the interface between liquid-ordered (Lo) and liquid-disordered (Ld) lipid phases. Our results demonstrate that the energetic cost of peptide insertion and subsequent membrane destabilization is significantly reduced at the domain boundaries due to increased local packing defects and higher lateral pressure. This preferential interaction at the Lo/Ld interface acts as a nucleation site, substantially increasing the probability of transmembrane pore formation compared to homogeneous lipid environments. These findings provide a mechanistic understanding of how membrane heterogeneity, a ubiquitous feature of cellular membranes, can modulate the efficacy of pore-forming agents and offer new insights for the rational design of targeted antimicrobial and drug delivery systems.