Participation of the g = 1.9 and g = 1.82 EPR forms of the semiquinone‐iron complex, QA −·Fe2+ of photosystem II in the generation of the Q and C thermoluminescence bands, respectively

FEBS Letters

Kovács, L.¹  Goussias, Ch.²  Petrouleas, V.²  Bernát, G.¹  Demeter, S.¹ 

[1] Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, PO Box 521, H-6701 Szeged, Hungary;Institute of Materials Science, NCSR ‘Demokritos’, Aghia Paraskevi Attikis, Greece

关键词: Photosystem II;    Semiquinone-iron complex;    Thermoluminescence;    Charge recombination;    EPR;    PS II;    photosystem II;    QA and QB;    primary and secondary quinone acceptors of PS II;    TL;    thermoluminescence;    EPR;    electron paramagnetic resonance;    DCMU;    3-(3;    4-dichlorophenyl)-1;    1-dimethyl-urea;    YD;    tyrosine-160 on the D2 protein;    accessory electron donor in PS II;    Chl;    chlorophyl;   

DOI  :  10.1016/0014-5793(93)80836-J

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Following illumination at 200 K, the charge recombination reactions and the origin of the thermoluminescence (TL) bands appearing at about 0°C (Q band) and +50°C (C band) in the glow curve were investigated by comparative TL and EPR measurements in DCMU-treated photosystem II particles. Decay half-time measurements carried out at −25°C and +25°C, respectively, suggest that the S₂ state (multi-line signal) undergoes charge recombination with the g = 1.9 form of the semiquinone-iron complex, Q_A ⁻·Fe²⁺, resulting in the appearance of the Q band, and that the g = 1.82 form of Q_A ⁻·Fe²⁺ back-reacts with the oxidized tyrosine, Y_D ⁺ (Signal II_s), accounting for the generation of the C band.

【 授权许可】

Unknown