Formation of the High-Spin S2State Related to the Extrinsic Proteins in the Oxygen Evolving Complex of Photosystem II

Shota Taguchi, Liangliang Shen, Guangye Han, Yasufumi Umena, Jian Ren Shen, Takumi Noguchi, Hiroyuki Mino

Research output: Contribution to journalArticlepeer-review

Abstract

The high-spin S2 state was investigated with photosystem II (PSII) from spinach, Thermosynechococcus vulcanus, and Cyanidioschyzon merolae. In extrinsic protein-depleted PSII, high-spin electron paramagnetic resonance (EPR) signals were not detected in either species, whereas all species showed g ∼5 signals in the presence of a high concentration of Ca2+ instead of the multiline signal. In the intact and PsbP/Q-depleted PSII from spinach, the g = 4.1 EPR signal was detected. These results show that formation of the high-spin S2 state of the manganese cluster is regulated by the extrinsic proteins through a charge located near the Mn4 atom in the Mn4CaO5 cluster but is independent of the intrinsic proteins. The shift to the g ∼5 state is caused by tilting of the z-axis in the Mn4 coordinates through hydrogen bonds or external divalent cations. The structural modification may allow insertion of an oxygen atom during the S2-to-S3 transition.

Original languageEnglish
Pages (from-to)8908-8913
Number of pages6
JournalJournal of Physical Chemistry Letters
Volume11
Issue number20
DOIs
Publication statusPublished - Oct 15 2020

ASJC Scopus subject areas

  • Materials Science(all)
  • Physical and Theoretical Chemistry

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