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

Tyrosine Z (Tyr Z ) oxidation observed at liquid helium temperatures provides new insights into the structure and function of Tyr Z in active Photosystem II (PSII). However, it has not been reported in PSII core complex from higher plants. Here, we report Tyr Z oxidation in the S 1 and S 2 states in...

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Bibliographic Details
Published in:Photosynthesis research 2009-02, Vol.99 (2), p.127-138
Main Authors: Ren, Yanan, Zhang, Chunxi, Bao, Han, Shen, Jianren, Zhao, Jingquan
Format: Article
Language:English
Subjects:
Biochemistry
Biomedical and Life Sciences
Electron Spin Resonance Spectroscopy
Electron Transport
Helium - chemistry
Life Sciences
Oxidation
Oxidation-Reduction
Phase Transition
Photosynthesis
Photosystem II Protein Complex - chemistry
Photosystem II Protein Complex - metabolism
Plant Genetics and Genomics
Plant Physiology
Plant Proteins - metabolism
Plant Sciences
Regular Paper
Spinacia oleracea - metabolism
Studies
Temperature
Tyrosine - chemistry
Tyrosine - metabolism
Vegetables
Water - metabolism
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Summary:Tyrosine Z (Tyr Z ) oxidation observed at liquid helium temperatures provides new insights into the structure and function of Tyr Z in active Photosystem II (PSII). However, it has not been reported in PSII core complex from higher plants. Here, we report Tyr Z oxidation in the S 1 and S 2 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 S 1 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 S 1 Tyr Z • EPR signal. Furthermore, EPR signals of the S 2 state of the Mn-cluster, the oxidation of the non-heme iron, and the S 1 Tyr Z • 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.
ISSN:0166-8595
1573-5079
DOI:10.1007/s11120-009-9410-x