Aromatic structure of Tyrosine-92 in the extrinsic PsbU protein of red algal Photosystem II is important for its functioning

Akinori Okumura, Masanori Sano, Takehiro Suzuki, Hiroyasu Tanaka, Ryo Nagao, Katsuyoshi Nakazato, Masako Iwai, Hideyuki Adachi, Jian-Ren Shen, Isao Enami

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PsbU is one of the extrinsic proteins in red algal Photosystem II (PSII) and functions to optimize the availability of Ca2+ and Cl- cofactors for water oxidation. To determine the functional residue of PsbU, we constructed various PsbU mutants from a red alga Cyanidium caldarium and reconstituted these mutants with the red algal PSII. The results revealed that Tyr-92 of PsbU, especially its aromatic ring, was essential for maintaining its function. From the crystal structure of PSII, Tyr-92 is located close to Pro-340 of D1, suggesting that the aromatic ring of Tyr-92 interacts with the CH group of Pro-340 of D1, and this CH/π interaction is important for the optimal function of the Mn4Ca-cluster.

Original languageEnglish
Pages (from-to)5255-5258
Number of pages4
JournalFEBS Letters
Issue number27
Publication statusPublished - Nov 13 2007



  • Extrinsic protein
  • Oxygen evolution
  • Photosystem II
  • PsbU
  • Red algae

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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