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Light‐induced degradation of cytochrome b 559 during photoinhibition of the photosystem II reaction center
Author(s) -
Ortega José M,
Roncel Mercedes,
Losada Manuel
Publication year - 1999
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/s0014-5793(99)01128-x
Subject(s) - photoinhibition , photosystem ii , photosynthetic reaction centre , photochemistry , chemistry , oxygen evolution , photosynthesis , cytochrome , oxygen , absorbance , singlet oxygen , photosystem , acceptor , biophysics , electron acceptor , cytochrome b , photosystem i , biology , biochemistry , enzyme , electron transfer , organic chemistry , chromatography , physics , electrode , electrochemistry , condensed matter physics , gene , mitochondrial dna
The behaviour of cytochrome (cyt) b 559 during acceptor‐ and donor‐side photoinhibition has been investigated in oxygen‐evolving and non‐evolving photosystem II (PSII) membranes. Strong illumination at 20°C under aerobiosis induced a strong decrease in the absorbance of the cyt b 559 α‐band in the two preparations. This absorbance decline was observed only in non‐oxygen‐evolving PSII samples when illumination was performed under aerobiosis but at 4°C, or under anaerobiosis at 20°C. These results suggest that acceptor‐side photoinhibition induces the degradation of cyt b 559 by a mechanism related to an enzymatic reaction mediated by singlet oxygen. Donor‐side photoinhibition may induce, however, a non‐enzymatic photocleavage of the protein.