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Can we trap the metalloradical intermediate during the S‐state transitions of Photosystem II? An EPR investigation
Author(s) -
Zahariou Georgia,
Chrysina Maria,
Petrouleas Vasili,
Ioannidis Nikolaos
Publication year - 2014
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2014.03.045
Subject(s) - photosystem ii , electron paramagnetic resonance , trapping , chemistry , oxygen evolving complex , photosystem i , photochemistry , oxygen , crystallography , nuclear magnetic resonance , photosynthesis , biology , physics , biochemistry , ecology , organic chemistry
We report the trapping of two metalloradical intermediates corresponding to the transitions S 2 to S 3 and S 3 to S 0 of the oxygen evolving complex (OEC) of Photosystem II (PSII), in preparations containing methanol, at temperatures near that of half inhibition of the respective S‐state transitions. The first intermediate, with an EPR width of 160 G, is assigned to , based on its similarity to the one previously characterized after trapping at 10 K. The second with a splitting of ∼80 G is tentatively assigned to . The EPR signal is weaker than the one, and both are stable at cryogenic temperatures.