Séminaire IBS : Seeing Hydrogens ! Cryo-EM provides insight into water and H-bonding networks in Photosystem II

Par Dr André Graca (EMBL Grenoble)

Photosystem II (PSII) is a pivotal membrane protein complex in oxygenic photosynthesis, catalysing the oxidation of water to molecular oxygen and initiating the photosynthetic electron transport chain.

Despite extensive structural studies, the precise locations of hydrogen atoms and water networks in PSII remained unclear, hindering full understanding of proton-coupled electron transfer mechanisms. In our recent study, using high-resolution cryo-electron microscopy data on fully hydrated PSII from Thermosynechococcus vestitus, we visualized over half of the hydrogen and proton positions at the core of the protein complex, offering direct insights into the hydrogen-bonding networks and partially occupied water sites at the water channels crucial for PSII function.

These findings provide a more comprehensive understanding of the structural basis for water oxidation and proton transport in PSII. The ability to directly observe hydrogen atoms and detailed water networks enhances our knowledge of the mechanisms driving photosynthetic water splitting and offers potential avenues for the design of artificial photosynthetic systems.

Hôte : Martin Weik (IBS/DYNAMOP) & Felix Weis (IBS/MEM)