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Annexin V and vesicle membrane electroporation
K Tönsing1, S Kakorin, E Neumann
1Physical and Biophysical Chemistry, Faculty of Chemistry, University of Bielefeld, Germany.
European Biophysics Journal : EBJ
|January 1, 1997
Summary
Membrane electroporation quantifies how membrane curvature and annexin V protein affect electric pore formation. Annexin V binding inhibits pore formation by altering lipid packing and reducing pore radius.
Area of Science:
- Biophysics
- Membrane Biology
- Protein-Lipid Interactions
Background:
- Membrane electroporation (ME) is a technique used to study lipid bilayer dynamics.
- Annexin V is a protein known to interact with lipid membranes, particularly in the presence of calcium ions.
Purpose of the Study:
- To quantify the influence of membrane curvature on electric pore formation using ME.
- To investigate the effect of annexin V adsorption on pore formation and membrane properties.
Main Methods:
- Utilized membrane electroporation (ME) as an analytical tool.
- Employed relaxation kinetic studies with optical membrane probes (diphenylhexatriene type).
- Analyzed data using Gibbs area-difference-elasticity energy principles.
Main Results:
- Electric pore formation is induced by ionic interfacial polarization, with a mean pore radius of 0.35 nm.
- Both the extent and rate of ME decrease with increasing vesicle radius and annexin V concentration.
- Annexin V adsorption leads to denser lipid packing and a reduction in electropore radius.
Conclusions:
- Annexin V exhibits an allosteric inhibitory effect on electroporation, saturating at approximately 4 microM.
- Bound annexin V reduces the lateral pressure gradient across the membrane.
- Protein insertion into the outer lipid leaflet alters membrane properties, decreasing electropore size.