Reconstitution of Purified VDAC1 into a Lipid Bilayer and Recording of Channel Conductance

Abstract

The functional properties of purified voltage-dependent anion-selective channel protein 1 (VDAC1) have been examined in reconstituted systems based on artificially prepared phospholipid bilayers. The most widespread method for the characterization of the pore-forming activity of the mitochondrial VDAC1 protein requires reconstitution of the channel activity into a planar lipid bilayer (PLB) that separates two aqueous compartments. This system is able to produce a refined and large set of information on channel activity. The activity of the channel is reflected in the flow of ions (i.e., current) through a membrane that otherwise represents a barrier to ion flow. The setup thus requires the use of purified protein and a source of continuous current, as well as a sophisticated detector system able to amplify and record low, picoamper-level currents. This system is so efficient that the activity of even a single channel can be detected, allowing for study of VDAC1 at the molecular level.