Effect of peptide length on the interaction between consensus peptides and DOPC/DOPA bilayers

Area of Science:

• Biophysics
• Biochemistry
• Membrane Biology

Background:

• Cardin motif peptides are studied for their interaction with lipid membranes.
• Understanding peptide-membrane interactions is crucial for developing new antimicrobial agents.

Purpose of the Study:

• To investigate the impact of peptide length and electrostatics on Cardin motif peptide interactions with lipid membranes.
• To determine how these interactions affect membrane leakage and bacterial viability.

Main Methods:

• Utilized fluorescence spectroscopy, circular dichroism, ellipsometry, z potential, and photon correlation spectroscopy.
• Investigated peptides (AKKARA)n and (ARKAAKKA)n with varying lengths (n=1-4 and n=1-3).
• Assessed leakage induction in zwitterionic and anionic liposomes and bacterial killing of E. faecalis and B. subtilis.

Main Results:

• Increased peptide length enhanced liposome leakage and bacterial killing.
• Peptide adsorption increased with length, plateauing at higher lengths.
• Peptide charges were critical for adsorption and leakage induction, with electrostatic effects influencing local packing.

Conclusions:

• Electrostatically affected local packing effects are crucial for the action of these peptides.
• While pore formation cannot be excluded, electrostatic interactions play a significant role in peptide-membrane disruption.
• Peptide length and charge are key determinants of antimicrobial activity and membrane interaction efficacy.