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Updated: Feb 26, 2026
Automated Lipid Bilayer Membrane Formation Using a Polydimethylsiloxane Thin Film
Published on: July 10, 2016
Single channel planar lipid bilayer recordings of the melittin variant MelP5
Aziz Fennouri1, Simon Finn Mayer2, Thomas B H Schroeder3
1Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland.
Abstract:
MelP5 is a 26 amino acid peptide derived from melittin, the main active constituent of bee venom, with five amino acid replacements. The pore-forming activity of MelP5 in lipid membranes is attracting attention because MelP5 forms larger pores and induces dye leakage through liposome membranes at a lower concentration than melittin. Studies of MelP5 have so far focused on ensemble measurements of membrane leakage and impedance; here we extend this characterization with an electrophysiological comparison between MelP5 and melittin using planar lipid bilayer recordings. These experiments reveal that MelP5 pores in lipid membranes composed of 3:1 phosphatidylcholine:cholesterol consist of an average of 10 to 12 monomers compared to an average of 3 to 9 monomers for melittin. Both peptides form transient pores with dynamically varying conductance values similar to previous findings for melittin, but MelP5 occasionally also forms stable, well-defined pores with single channel conductance values that vary greatly and range from 50 to 3000pS in an electrolyte solution containing 100mM KCl.
Insights
MelP5, a melittin derivative, forms larger, more stable pores in lipid membranes than melittin. Electrophysiological studies reveal MelP5 pores comprise more monomers and exhibit unique stable pore formation, offering new insights into peptide-membrane interactions.
Area of Science:
- Biophysics
- Membrane Biology
- Peptide Science
Background:
- Melittin, a bee venom component, is known for its pore-forming activity in lipid membranes.
- MelP5, a modified melittin peptide, exhibits enhanced pore formation and dye leakage at lower concentrations.
- Previous studies primarily used ensemble measurements, necessitating detailed electrophysiological characterization.
Purpose of the Study:
- To electrophysiologically compare the pore-forming activity of MelP5 and melittin using planar lipid bilayer recordings.
- To elucidate the structural differences in pore formation between MelP5 and melittin.
- To characterize the conductance properties and stability of pores formed by both peptides.
Main Methods:
- Planar lipid bilayer electrophysiology.
- Conductance measurements of peptide-induced pores.
- Analysis of pore stability and monomer composition.
Main Results:
- MelP5 pores in phosphatidylcholine:cholesterol membranes consist of an average of 10–12 monomers, versus 3–9 for melittin.
- Both peptides form transient pores with dynamic conductance.
- MelP5 uniquely forms stable, well-defined pores with single-channel conductance ranging from 50–3000pS (100mM KCl).
Conclusions:
- MelP5 exhibits distinct pore-forming characteristics compared to melittin, forming larger and occasionally stable pores.
- Electrophysiological recordings provide a detailed understanding of MelP5's membrane interaction.
- These findings highlight MelP5's potential for applications requiring controlled membrane disruption.
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