Molecular Dynamics Simulations of Membrane Selectivity of Star Peptides Across Different Bacterial and Mammalian Bilipids

TL;DR

This study uses molecular dynamics simulations to reveal how nanoengineered antimicrobial peptides selectively bind bacterial membranes while avoiding mammalian cells, guiding future antimicrobial design.

Contribution

It provides detailed molecular insights into the membrane selectivity mechanism of SNAPPs, a novel class of antimicrobial polymers.

Findings

SNAPP binds rapidly and stably to bacterial membranes via electrostatic interactions.

Mammalian membranes resist SNAPP binding due to lipid composition and cholesterol content.

SNAPP remains excluded from host membranes while targeting bacterial bilayers.

Abstract

Structurally nanoengineered antimicrobial peptide polymers (SNAPPs) are emerging as promising selective agents against bacterial membranes. In this study, we used all atom molecular dynamics simulation techniques to investigate the interaction of a promising cationic SNAPP architecture (Alt-SNAPP with 8 arms made of alternating lysine and valine residues) with modelled Gram-negative, Gram-positive, mammalian, and red blood cell membranes. Alt-SNAPP exhibited rapid and stable binding to bacterial membranes, driven by electrostatic interactions with anionic lipids such as phosphatidylglycerol (PG) and cardiolipin (CL), and supported by membrane fluidity. In contrast, mammalian and red blood cell membranes, enriched in zwitterionic lipids and cholesterol, resisted peptide association entirely. Analyses of center of mass distance, partial density, hydrogen bonding, and interaction energy confirmed that SNAPP remains fully excluded from host like membranes while forming stable, multivalent interactions with bacterial bilayers. These findings provide mechanistic insight into membrane selectivity of SNAPP and offer a molecular framework for designing next generation antimicrobial polymers with minimal off target toxicity.