Photochemistry: Light-Activated Molecular Wires and Solar Fuels.
Multiheme cytochromes are proposed as Nature’s solution to long-range electron transfer. These novel proteins enable electrons to be transported within, between and outside of bacteria, sometimes over distances greatly exceeding cellular dimensions. Electron transfer is through complementary Fe(III) to Fe(II) transitions of neighbouring hemes which are arranged as chains spanning the proteins’ structures. We apply a rational approach to activate multiheme cytochromes for light-driven long-range electron transfer whereby synthetic photosensitisers absorb visible-light creating energised electrons that are passed into the multiheme cytochromes. The resulting biohybrid materials aims to combine long-range electron transfer through renewable molecules with synthetic materials having that prospects of improved absorption over the incident solar spectrum and photostability when compared to natural Photosystems. Our photosensitised multiheme cytochromes are studied to reveal fundamental characteristics of electron transfer within these proteins and to inspire design concepts for technology delivering solar chemicals, including fuels.
Our primary focus for these studies are the multiheme cytochromes of Shewanella oneidensis. This bacterium is a model organism for resolving the biochemistry and biophysics of multiheme cytochromes and a chassis for biotechnology exploiting electron transfer across the extracellular envelope.
Adv. Funct. Mater. 2015