(Invited) Proton Pump for Solar Energy Transformation:from Nano- to Meso-Scale Architectures

Abstract

Proton pumps are group of membrane proteins which carry out proton (H+) transfer across a biological membrane via energy-driven conformational changes in their structures. Light-driven proton pumps utilize sunlight energy to fuel ATP-synthase. Light is absorbed by the retinal cofactor that results in photoisomeriazation of the chromophore that leads to proton translocation through a membrane. Earlier we demonstrated that semiconductor nanoparticles can be self-assembled with membrane-proton pump complexes known as purple membranes (PM), wherein PM can be either isolated from microorganism as micron-scale patches [1,2] or synthesized cell-free as nano-sized particles [3]. These bio-inorganic constructs can be used for efficient water splitting systems in photocatalytic hydrogen production half-reaction. Catalytic activity of these assemblies can be boosted via variety of approaches, for example, control and scaling down of the soft material dimensions [3], introduction of a single atomic layer carbon material [2]. Further efforts are directed toward more complex meso-scale artificial systems for sunlight energy transformation to other fuels and useful products. 1.S. Balasubraanian, P. Wang, R. Schaller, T. Rajh, E.A. Rozhkova, NanoLetters 13, 3365−3371 (2013) P. Wang, N.M. Dimitrijevic, A.Y. Chang, R.D. Schaller, Y. Liu, T. Rajh, E.A. Rozhkova, ACS Nano, 8(8), 7995-8002 (2014)P. Wang, A. Y. Chang, V. Novosad, V. V. Chupin, R.D. Schaller, E. A. Rozhkova, ACS Nano, 11 (7), pp 6739–6745 (2017)