Design of energy-transducing artificial cells

Abstract

A sustainable society requires sources of renewable energy that are efficient, cost-effective, and robust. Achieving such energy sources represents a significant challenge that requires the development of novel technologies, including the creation of materials that control physical and chemical transformations at a molecular level. Photosynthesis performs solar energy conversion using Earth-abundant metals, a broad spectral range, and materials that operate under ambient conditions. The components of photosynthetic systems work cooperatively and efficiently with enviable rates, providing the motivation for using these components in energy transduction strategies. In PNAS, Altamura et al. (1) move us closer toward this goal by demonstrating how protein complexes from photosynthetic bacteria can be incorporated into artificial cells to convert light into chemical energy, in the form of a proton gradient, using new technical approaches that should be of general applicability. Since the pioneering work of Mitchell (2), it has been recognized that organisms use differences in proton concentrations across the cell membrane, termed proton gradients, to perform energy transduction. Biochemical reactions are coupled with the transfer of protons across the membrane through the use of proteins present in the membrane. For example, the membrane protein ATP synthase uses proton transfer to form the energy-rich compound ATP from ADP. In bacterial photosynthesis, the formation of the proton gradient is driven by the absorption of light by a pigment–protein complex called the reaction center (3). The reaction center is a membrane protein containing a number of cofactors arranged in two branches that span the membrane (Fig. 1). Light energy is … [↵][1]1Email: jallen{at}asu.edu. [1]: #xref-corresp-1-1