Functional reconstitution of photosynthetic reaction centers in planar lipid bilayers

Abstract

Planar lipid bilayers containing reaction centers from Rhodopseudomonas sphaeroides R-26 were formed by apposing 2 reaction center-lipid monolayers formed from a reaction center-lipid complex in hexane. Secondary donors (cytochrome c) and acceptors (ubiquinone-O) were added on opposite sides of the membrane. Upon illumination, this system generated transient and steady-state voltages and currents. The wavelength dependence of the photoresponse matched the absorption spectrum of reaction centers. A simple model based on the transfer of charges across the membrane that explains the salient features of the photoresponse is presented.