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Updated: Feb 8, 2026

Purification of Active Photosystem I-Light Harvesting Complex I from Plant Tissues
Published on: February 3, 2023
Structural changes in the S3 state of the oxygen evolving complex in photosystem II
Makoto Hatakeyama1, Koji Ogata1, Katsushi Fujii2
1RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Abstract:
The S3 state of the Mn4 CaO5 -cluster in photosystem II was investigated by DFT calculations and compared with EXAFS data. Considering previously proposed mechanism; a water molecule is inserted into an open coordination site of Mn upon S2 to S3 transition that becomes a substrate water, we examined if the water insertion is essential for the S3 formation, or if one cannot eliminate other possible routes that do not require a water insertion at the S3 stage. The novel S3 state structure consisting of only short 2.7-2.8 Å Mn-Mn distances was discussed.
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