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Alamethicin adsorption to a planar lipid bilayer
I Vodyanoy1, J E Hall, V Vodyanoy
1Department of Physiology and Biophysics, University of California, Irvine 92717.
Biophysical Journal
|May 1, 1988
Summary
Alameticin and its derivatives alter voltage-dependent capacitance in phosphatidylethanolamine membranes. This effect, a potential-dependent pseudocapacitance, is linked to adsorbed alamethicin molecules and their interactions.
Area of Science:
- Biophysics
- Membrane Biophysics
- Ion Channel Function
Background:
- Voltage-dependent capacitance is crucial for membrane function.
- Alameticin is a peptide antibiotic known to form pores in membranes.
- Understanding alamethicin's interaction with lipid bilayers provides insights into membrane electrostatics.
Purpose of the Study:
- To investigate the effect of alamethicin and its derivatives on voltage-dependent capacitance.
- To characterize the nature of alamethicin-induced capacitance changes.
- To develop a theoretical model explaining the observed phenomena.
Main Methods:
- Measurement of voltage-dependent capacitance using lock-in detection and voltage pulse techniques.
- Utilizing phosphatidylethanolamine (squalane) membranes.
- Quantitative analysis of capacitance changes based on alamethicin concentration and applied electric field.
Main Results:
- Alameticin and derivatives modulate capacitance at voltages below conductance detection.
- Capacitance changes are dependent on alamethicin concentration and type.
- Experimental data support a model of potential-dependent pseudocapacitance due to adsorbed alamethicin.
Conclusions:
- Alameticin adsorption induces a pseudocapacitance on membranes.
- This pseudocapacitance is influenced by alamethicin charge, concentration, and electric field.
- Interactions between adsorbed alamethicin molecules affect the observed capacitance, with interaction energy dependent on concentration.