Probing tyrosine Z oxidation in photosystem II core complex isolated from spinach by EPR at liquid helium temperatures

Yanan Ren, Chunxi Zhang, Han Bao, Jianren Shen, Jingquan Zhao

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4 Citations (Scopus)


Tyrosine Z (TyrZ) oxidation observed at liquid helium temperatures provides new insights into the structure and function of TyrZ in active Photosystem II (PSII). However, it has not been reported in PSII core complex from higher plants. Here, we report TyrZ oxidation in the S1 and S2 states in PSII core complex from spinach for the first time. Moreover, we identified a 500 G-wide symmetric EPR signal (peak position g = 2. 18, trough position g = 1. 85) together with the g = 2. 03 signal induced by visible light at 10 K in the S1 state in the PSII core complex. These two signals decay with a similar rate in the dark and both disappear in the presence of 6% methanol. We tentatively assign this new feature to the hyperfine structure of the S1TyrZ EPR signal. Furthermore, EPR signals of the S2 state of the Mn-cluster, the oxidation of the non-heme iron, and the S1TyrZ in PSII core complexes and PSII-enriched membranes from spinach are compared, which clearly indicate that both the donor and acceptor sides of the reaction center are undisturbed after the removal of LHCII. These results suggest that the new spinach PSII core complex is suitable for the electron transfer study of PSII at cryogenic temperatures.

Original languageEnglish
Pages (from-to)127-138
Number of pages12
JournalPhotosynthesis research
Issue number2
Publication statusPublished - Feb 1 2009



  • EPR
  • Photosystem II core complex
  • Spinach
  • Tyrosine Z

ASJC Scopus subject areas

  • Biochemistry
  • Plant Science
  • Cell Biology

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