Melittin is an interfacially active a-helix that causes membrane destabilization via a mechanism that is still disputed.  While a transmembrane pore model has been a central part of the mechanistic dialogue for decades, there is growing evidence that a transmembrane pore is not required for melittin activity.  In part, the controversy is due to limited experimental tools to probe the bilayer's response to melittin.  Electrochemical impedance spectroscopy (EIS) is a technique that can reveal details of molecular mechanism of peptide activity, as it yields direct measurements of membrane resistance and capacitance of supported bilayers.  In the work presented here, this technique was used to study the response of surface-supported bilayers of different lipid compositions to melittin.  The EIS results directly demonstrate that the interfacial response of a bilayer to melittin cannot be explained by a simple transmembrane pore model.

Electrical response of lipid bilayers to the bee venom toxin melittin using electrochemical impedance spectroscopy

245th National Meeting (2013)

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