Untangling the sequence of events during the S₂ → S₃ transition in photosystem II and implications for the water oxidation mechanism.

ABSTRACT: In oxygenic photosynthesis, light-driven oxidation of water to molecular oxygen is carried out by the oxygen-evolving complex (OEC) in photosystem II (PS II). Recently, we reported the room-temperature structures of PS II in the four (semi)stable S-states, S₁, S₂, S₃, and S₀, showing that a water molecule is inserted during the S₂ → S₃ transition, as a new bridging O(H)-ligand between Mn1 and Ca. To understand the sequence of events leading to the formation of this last stable intermediate state before O₂ formation, we recorded diffraction and Mn X-ray emission spectroscopy (XES) data at several time points during the S₂ → S₃ transition. At the electron acceptor site, changes due to the two-e

SUBMITTER: Ibrahim M 

PROVIDER: S-EPMC7293653 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature