Pardaxin permeabilizes vesicles more efficiently by pore formation than by disruption
Brian S Vad1, Kresten Bertelsen, Charlotte Hau Johansen
1Department of Molecular Biology, University of Aarhus, Aarhus, Denmark.
Biophysical Journal
|February 18, 2010
Summary
Pardaxin neurotoxin
Area of Science:
- Biochemistry
- Biophysics
- Membrane Biology
Background:
- Pardaxin, a neurotoxin from the Moses sole, interacts with lipids.
- Its mechanism is sensitive to lipid properties but pH effects are unclear.
Purpose of the Study:
- To elucidate the pH-dependent interaction of pardaxin with lipids.
- To understand pardaxin's pore formation and membrane lysis mechanisms.
Main Methods:
- Optical spectroscopy
- Dye release experiments
- Confocal microscopy
- Solid-state nuclear magnetic resonance (NMR)
Main Results:
- Pardaxin-induced calcein release is highly pH-sensitive.
- Low pH favors release from zwitterionic (PC) vesicles; high pH favors release from anionic (PG) vesicles.
- Pardaxin forms pores in PC vesicles but causes lysis in PG-containing vesicles.
- NMR shows transmembrane orientation in PC bicelles and headgroup interaction in PG-containing membranes.
Conclusions:
- Pardaxin's interaction with lipids is strongly pH-dependent.
- Electrostatic interactions with anionic lipids may hinder pore formation.
- Pardaxin exhibits distinct membrane interaction modes based on lipid charge and pH.
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