Light‐induced degradation of cytochrome b559 during photoinhibition of the photosystem II reaction center

FEBS Letters

Losada, Manuel¹  Roncel, Mercedes¹  Ortega, José M¹ 

[1] Instituto de Bioquı́mica Vegetal y Fotosı́ntesis, Universidad de Sevilla y CSIC, Americo Vespucio s/n, 41092 Sevilla, Spain

关键词: Cytochrome b559;    Degradation;    Photoinhibition;    Photosystem II;    Chl;    chlorophyll;    cyt;    cytochrome;    DCPIP;    2;    6-dichlorophenol-indo-phenol;    E′m;    midpoint redox potential;    HP and LP;    high- and low-potential forms of cyt b559;    Mn;    manganese;    PAGE;    polyacrylamide gel electrophoresis;    PSII;    photosystem II;    P680;    primary donor of PSII;    QA;    primary quinone acceptor;    QB;    secondary quinone acceptor;    RC;    reaction center;    SDS;    sodium dodecyl sulfate;    TL;    thermoluminescence;   

DOI  :  10.1016/S0014-5793(99)01128-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The behaviour of cytochrome (cyt) b559 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 b559 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 b559 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.

【 授权许可】

Unknown