Characterization by FTIR spectroscopy of the photoreduction of the primary quinone acceptor QA in photosystem II

FEBS Letters

Nabedryk, E.¹  Breton, J.¹  Mäntele, W.²  Berthomieu, C.¹ 

[1] Service de Biophysique, CEN Saclay, 91191 Gif-sur-Yvette cedex, France;Institut für Biophysik und Strahlenbiologie, Universität Freiburg, Albertsir. 23, D-7800 Freiburg, FRG

关键词: Fourier transform infrared difference spectroscopy;    Photosystem II;    Primary quinone acceptor;    Plastoquinone;    FTIR;    Fourier transform infrared;    PS II;    photosystem II;    RC;    reaction center;    Rps.;    Rhodopseudomonas;    Rb.;    Rhodobacter;    QA;    primary quinone acceptor;    P680;    primary electron donor;    BBY;    PS II-enriched membranes;    Mes;    2-(N-morpholino)ethanesulphonic acid;    Tris;    tris(hydroxymethyl)aminomethane;    DCMU;    diuron;    3-(3;    4dichlorophenyl)-1;    1-dimethylurea;    Chl;    chlorophyll;    Tyrz;    secondary electron donor tyrosine D1161;    PQ-9;    plastoquinone-9;    3-MBQ;    trimethylbenzoquinone;    THF;    tetrahydrofuran;   

DOI  :  10.1016/0014-5793(90)81194-S

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Molecular changes associated with the photoreduction of the primary quinone acceptor Q_a of photosystem II have been characterized by Fourier transform infrared spectroscopy. This reaction was light-induced at room temperature on photosystem II membranes in the presence of hydroxylamine and diuron. A positive signal at 1478 cm⁻¹ is assigned to the C⋯O stretching mode of the semiquinone anion, and can be correlated to the negative C=O mode(s) of the neutral Q_A at 1645 cm⁻¹ and/or 16 cm⁻¹. Analogies with bacterial reaction center are found in the amide I absorption range at 1672 cm⁻¹, 1653 cm⁻¹ and 1630 cm⁻¹. The stabilization of Q_A ⁻ does not result from a large protein conformation change, but involves perturbations of several amino acid vibrations. At 1658 cm⁻¹, a negative feature sensitive to ¹H–²H exchange is tentatively assigned to a δNH₂ histidine mode, while tryptophan D₂252 could contribute to the signal at cm⁻¹.

【 授权许可】

Unknown