Title:  Engineering new proteins for enhanced photosynthesis

Abstract: Plants, green algae, and cyanobacteria power the biosphere using oxygenic photosynthesis to oxidize water to oxygen and liberate high-energy electrons for carbon fixation.  Despite its evolutionary success, oxygenic photosynthesis has a low overall efficiency.  It fails to make use of the abundant energy in the near-infrared region of the solar spectrum, and it loses energy to thermalization and inefficient charge separation.   We leverage recent developments in AI methods for protein design such as AlphaFold, RFdiffusion, and ProteinMPNN to engineer new high-efficiency photosystems that control light-activated electron tunneling, use excitonic coupling to tune spectroscopic properties of chromophores, assemble novel metal clusters, and catalyze redox reactions.  We characterize the designs using spectroscopy, electrochemistry, cryo-electron microscopy, and X-ray crystallography.  This research project may lead to enhanced photosynthesis for improved production of renewable solar fuels, sustainable ammonia for fertilizer, and faster-growing crops for food.