Voltage-gated lipid ion channels

TL;DR

This study demonstrates that synthetic lipid membranes exhibit voltage-gated ion conduction events with properties similar to protein channels, supported by experimental data and a theoretical model.

Contribution

It provides a theoretical and experimental analysis of voltage-gated lipid ion channels, showing their behavior parallels that of protein channels.

Findings

Lipid channels display quadratic voltage dependence.

Theoretical model fits experimental data well.

Open and closed state distributions differ from exponential.

Abstract

Synthetic lipid membranes can display channel-like ion conduction events even in the absence of proteins. We show here that these events are voltage-gated with a quadratic voltage dependence as expected from electrostatic theory of capacitors. To this end, we recorded channel traces and current histograms in patch-experiments on lipid membranes. We derived a theoretical current-voltage relationship for pores in lipid membranes that describes the experimental data very well when assuming an asymmetric membrane. We determined the equilibrium constant between closed and open state and the open probability as a function of voltage. The voltage-dependence of the lipid pores is found comparable to that of protein channels. Lifetime distributions of open and closed events indicate that the channel open distribution does not follow exponential statistics but rather power law behavior for long open times.