Donor‐side photoinhibition in photosystem II from Chlamydomonas reinhardtii upon mutation of tyrosine‐Z in the D1 polypeptide to phenylalanine

FEBS Letters

Kanazawa, Atsuko¹  Minagawaa, Jun¹  Crofts, Antony R.¹  Kramer, David M.² 

[1] Center for Biophysics and Computational Biology, University of Illinois, 505 S. Goodwin Ave., Urbana, IL 61801, USA;Department of Plant Biology, University of Illinois, 505 S. Goodwin Ave., Urbana, IL 61801, USA

关键词: Photosystem 11;    Photoinhibition;    Carotenoid;    Tyrosine-Z Active oxygen abr|P680;    primary electron donor chlorophyll(s);    PS 11;    photosystem II;    QA;    primary quinone acceptor in PS II;    YZ;    tyrosine-161 residue on the D1 protein;    C. reinhardtii;    Chlamydomonas reinhardtii;    SOD;    superoxide dismutase;    DCMU;    3(3;    4-dichlorophenyl)-1;    1-dimethyl urea;    Car;    carotenoid;   

DOI  :  10.1016/0014-5793(96)00581-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

When tyrosine-Z of the D1-polypeptide of the photosystem II from Chlamydomonas reinhardtii was changed to phenylalanine, the rapid donor to P680⁺ was lost, and P680⁺ accumulated on illumination. The rapid donation from tyrosine-Z was replaced by a slow electron transfer from an endogenous donor. Spectrophotometric measurements showed that carotenoids and chlorophylls were bleached by the P₆₈₀ ⁺ either directly or indirectly upon illumination. The carotenoid bleaching was inhibited in the presence of SOD or catalase, but the reaction did not require molecular oxygen as an electron acceptor. These observations led us to conclude that active oxygen radicals, possibly hydroxyl radicals, take part in the destruction of carotenoids in the Y161F mutant. Possible mechanisms for the destruction are discussed.

【 授权许可】

Unknown