Letters to Nature

Nature 392, 479-482 (2 April 1998) | doi:10.1038/33116; Received 13 November 1997; Accepted 16 February 1998

Light-driven production of ATP catalysed by F0F1-ATP synthase in an artificial photosynthetic membrane

Gali Steinberg-Yfrach1, Jean-Louis Rigaud2, Edgardo N. Durantini1, Ana L. Moore1, Devens Gust1 & Thomas A. Moore1

  1. Department of Chemistry and Biochemistry and Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604, USA
  2. Institut Curie, Section de Recherche, UMR-CNRS 168 and LCR-CEA 8, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05, France

Correspondence to: Thomas A. Moore1 Correspondence and requests for materials should be addressed to T.A.M. (e-mail: Email: tmoore@asu.edu).

Energy-transducing membranes of living organisms couple spontaneous to non-spontaneous processes through the intermediacy of protonmotive force (p.m.f.) — an imbalance in electrochemical potential of protons across the membrane. In most organisms, p.m.f. is generated by redox reactions that are either photochemically driven, such as those in photosynthetic reaction centres, or intrinsically spontaneous, such as those of oxidative phosphorylation in mitochondria. Transmembrane proteins (such as the cytochromes and complexes I, III and IV in the electron-transport chain in the inner mitochondrial membrane) couple the redox reactions to proton translocation, thereby conserving a fraction of the redox chemical potential as p.m.f. Many transducer proteins couple p.m.f. to the performance of biochemical work, such as biochemical synthesis and mechanical and transport processes. Recently, an artificial photosynthetic membrane was reported in which a photocyclic process was used to transport protons across a liposomal membrane, resulting in acidification of the liposome's internal volume1. If significant p.m.f. is generated in this system, then incorporating an appropriate transducer into the liposomal bilayer should make it possible to drive a non-spontaneous chemical process. Here we report the incorporation of FOF1-ATP synthase into liposomes containing the components of the proton-pumping photocycle. Irradiation of this artificial membrane with visible light results in the uncoupler- and inhibitor-sensitive synthesis of adenosine triphosphate (ATP) against an ATP chemical potential of approx12 kcal mol-1, with a quantum yield of more than 7%. This system mimics the process by which photosynthetic bacteria convert light energy into ATP chemical potential.