Lipidation-induced bacterial cell membrane translocation of star-peptides

TL;DR

This study uses molecular dynamics to show how lipidation improves the membrane translocation and antibacterial activity of star-shaped peptide polymers, offering insights for designing effective antimicrobials against resistant bacteria.

Contribution

It demonstrates how different lipid chain lengths affect SNAPPs' stability, membrane interaction, and translocation, providing a framework for optimizing antimicrobial peptide design.

Findings

Lipidation with C12 enhances bilayer disruption.

C6 lipidation improves membrane insertion.

Excessive C18 lipidation reduces effectiveness due to arm back-folding.

Abstract

The rapid emergence of multidrug-resistant (MDR) bacteria demands development of novel and effective antimicrobial agents. Structurally Nanoengineered Antimicrobial Peptide Polymers (SNAPPs), characterized by their unique star-shaped architecture and potent multivalent interactions, represent a promising solution. This study leverages molecular dynamics simulations to investigate the impact of lipidation on SNAPPs' structural stability, membrane interactions, and antibacterial efficacy. We show that lipidation with hexanoic acid (C6), lauric acid (C12), and stearic acid (C18) enhances the {\alpha}-helical stability of SNAPP arms, facilitating deeper insertion into the hydrophobic core of bacterial membranes. Among the variants, C12-SNAPP exhibits the most significant bilayer disruption, followed by C6-SNAPP, whereas the excessive hydrophobicity of C18-SNAPP leads to pronounced arm back-folding towards the core, reducing its effective interaction with the bilayer and limiting its bactericidal performance. Additionally, potential of mean force (PMF) analysis reveals that lipidation reduces the free energy barrier for translocation through the bilipid membrane compared to non-lipidated SNAPPs. These findings underscore the critical role of lipidation in optimizing SNAPPs for combating MDR pathogens. By fine-tuning lipid chain lengths, this study provides a framework for designing next-generation antimicrobial agents to address the global antibiotic resistance crisis, advancing modern therapeutic strategies.