Selective Interaction of the Antimicrobial Peptide RKW with Bacterial Lipid Bilayers: A Biophysical Approach

Area of Science:

• Biophysics
• Antimicrobial Peptides
• Membrane Biology

Background:

• Antimicrobial peptides (AMPs) show potential against multidrug-resistant bacteria but face limitations due to host cell toxicity.
• Understanding AMP-membrane interactions is crucial for developing safer therapeutics.

Purpose of the Study:

• Investigate the interaction of the designed AMP, RKW, with model membranes.
• Determine RKW's selectivity and mechanism of action against bacterial versus eukaryotic membranes.

Main Methods:

• Utilized model lipid vesicles mimicking prokaryotic and eukaryotic membranes.
• Employed fluorescence spectroscopy, quenching experiments, and dynamic light scattering (DLS).
• Conducted toxicological assessments using *Caenorhabditis elegans*.

Main Results:

• RKW demonstrated strong preference for negatively charged bacterial membranes, especially Gram-negative models.
• Peptide localized at the membrane interface, likely parallel to the bilayer.
• RKW induced significant carboxyfluorescein leakage from bacterial models, indicating membrane permeabilization.
• In vivo studies showed no adverse effects of RKW on *C. elegans*.

Conclusions:

• RKW exhibits selective membrane targeting driven by electrostatic interactions.
• The peptide effectively permeabilizes bacterial membranes with minimal host cell toxicity.
• RKW presents potential as a targeted antimicrobial agent with a favorable safety profile.