Molecular interactions of the redox‐active accessory chlorophyll on the electron‐donor side of photosystem II as studied by Fourier transform infrared spectroscopy

FEBS Letters

Takumi, Noguchi¹  Yorinao, Inoue¹ 

[1] Photosynthesis Research laboratory, Solar Energy Research Group, The Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351-01, Japan

关键词: Photosynthesis;    Photosystem II;    Fourier transform infrared spectroscopy;    Chlorophyll;    Radical cation;    Chl;    chlorophyll a in vitro;    Chlz;    redox-active accessory chlorophyll of PS II;    cyt b 559;    cytochrome b 559;    ESR;    electron spin resonance;    FTIR;    Fourier transform infrared;    MES;    2-(N-morpholino)ethanesulfonic acid;    P680;    primary electron donor;    PS II;    photosystem II;    QA;    primary quinone acceptor;    THF;    tetrahydrofuran;    Y d;    tyrosine electron donor in the D2 subunit;    Y z;    tyrosine electron donor in the D1 subunit;   

DOI  :  10.1016/0014-5793(95)00833-U

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

A Fourier transform infrared (FTIR) difference spectrum upon photooxidation of the accessory chlorophyll (Chl_z) of photosystem II (PS II) was obtained at 210 K with Mn-depleted PS II membranes in the presence of fericyanide and silicomolybdate. The observed Chl_z ⁺/Chl_z spectrum showed two differential bands at 1747/1736 and 1714/1684 cm⁻. The former was assigned to the free carbomethoxy C = 0 and the latter to the keto C = 0 that is hydrogen-bonded or in a highly polar environment. Also, the negative 1614 cm⁻ band assignable to the macrocycle mode indicated 5-coordination of the central Mg. The negative 1660 cm⁻¹ band, possibly due to the strongly hydrogen-bonded keto C = 0, may suggest oxidation of one more Chl_z, although an alternative assignment, the amide I mode of proteins perturbed by Chl_z oxidation, is also possible.

【 授权许可】

Unknown