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A Bioinspired Mastoparan Exhibits Concentration-Dependent Anti-Bacterial Activity via Membrane Disruption
Gisele R Rodrigues1,2, Marco Fornasier2, Lucrezia Caselli2
1Centro de Análises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, Distrito Federal 70790160, Brazil.
Abstract:
Antimicrobial peptides are widely investigated in the literature, but their mechanism of action and effects on lipid membranes are not completely understood from a physicochemical perspective. In this study, we employed a bioinspired mastoparan from wasp venom, mast-MO, and characterized its interactions with model lipid membranes, either as a supported lipid bilayer or as free-standing vesicles in solution. An array of complementary physicochemical characterization techniques was employed to study the surface activity of the peptide alone and how its adsorption affects lipid membrane properties in terms of lateral organization and integrity. We found that peptide action is related to its intrinsic surface activity, resulting in disrupted lipid packing of supported membranes and vesicles via a concentration-dependent mechanism. Changing solution conditions, e.g., ionic strength and pH, altered the electrostatic interactions between the membrane and mast-MO, resulting in less significant adsorption. This mechanism of action was also validated in vitro for Gram-negative E. coli bacteria, demonstrating rapid action (within 15 min) and potent antimicrobial activity. These results provide new information on the molecular effects of mastoparan's interactions with membranes.
Insights
This study reveals how mastoparan peptides disrupt lipid membranes, offering insights into antimicrobial peptide mechanisms. The research highlights peptide surface activity and its concentration-dependent effects on membrane integrity.
Area of Science:
- Biophysics
- Biochemistry
- Membrane Biophysics
Background:
- Antimicrobial peptides (AMPs) are crucial in innate immunity, but their physicochemical mechanisms of action on lipid membranes remain unclear.
- Understanding AMP-membrane interactions is vital for developing new antimicrobial strategies.
Purpose of the Study:
- To investigate the physicochemical interactions between a bioinspired mastoparan peptide (mast-MO) and model lipid membranes.
- To elucidate the mechanism by which mast-MO affects membrane organization and integrity.
Main Methods:
- Utilized a bioinspired mastoparan (mast-MO) and characterized its interactions with supported lipid bilayers and vesicles.
- Employed complementary physicochemical techniques to analyze peptide surface activity and membrane property alterations.
- Validated the mechanism of action in vitro against Gram-negative E. coli.
Main Results:
- Mast-MO exhibits intrinsic surface activity, disrupting lipid packing in a concentration-dependent manner.
- Changes in ionic strength and pH modulate electrostatic interactions, reducing mast-MO adsorption to membranes.
- Demonstrated rapid and potent antimicrobial activity against E. coli.
Conclusions:
- Mastoparan peptide action is linked to surface activity, leading to membrane disruption.
- Environmental factors like ionic strength and pH significantly influence peptide-membrane interactions.
- Mast-MO shows potential as a rapid-acting antimicrobial agent against Gram-negative bacteria.
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