The electron-proton bottleneck of photosynthetic oxygen evolution.

ABSTRACT: Photosynthesis fuels life on Earth by storing solar energy in chemical form. Today's oxygen-rich atmosphere has resulted from the splitting of water at the protein-bound manganese cluster of photosystem II during photosynthesis. Formation of molecular oxygen starts from a state with four accumulated electron holes, the S₄ state-which was postulated half a century ago¹ and remains largely uncharacterized. Here we resolve this key stage of photosynthetic O₂ formation and its crucial mechanistic role. We tracked 230,000 excitation cycles of dark-adapted photosystems with microsecond infrared spectroscopy. Combining these results with computational chemistry reveals that a crucial proton vacancy is initally created through gated sidechain deprotonation. Subsequ

SUBMITTER: Greife P 

PROVIDER: S-EPMC10191853 | biostudies-literature | 2023 May

REPOSITORIES: biostudies-literature