Catalytic Electron Transfer in Photosystem II of Plants and Bacteria

Photosystem II is the principal light trapping protein assembly driving the photoelectric conversion of light into metabolic energy in nature. It does this by extracting electrons from water and releasing them in energy rich compounds within plants. The separate light-activated and water oxidising regions of the photosystem protein execute very different, incompatible chemistries. They are linked by electron proton transfer reactions, of uniquely efficient characteristics, which are currently not understood. This project will reveal the mechanism and molecular detail of these linking reactions and determine whether biochemical adaptations in them have occurred over evolutionary time as atmospheric carbon dioxide levels changed.