Nanosecond electron transfer kinetics in photosystem I following substitution of quinones for vitamin K1 as studied by time resolved EPR

FEBS Letters

van der Est, Arthur²  Sieckman, Ina²  Bottin, Hervé¹  Sétif, Pièrre¹  Stehlik, Dietmar² 

[1] Service de Biophysique, Département de Biologie CEN de Saclay, F-91191 Gif-sur-Yvette, France;Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-1000 Berlin 33, Germany

关键词: Photosystem I;    Vitamin K1;    Electron transfer;    Time resolved EPR;    A1 extraction/reconstitution;    Synechocystis 6803;    A;    absorption;    DQ;    duroquinone;    DQd12;    perdeuterated duroquinone;    E;    emission;    ESP;    electron spin polarization;    (FeS);    iron sulfur center;    hfs;    hyperfine structure;    MW;    microkwave;    NQ;    naphthoquinone;    PS I;    photosystem I;    Q;    quinone;    VK1;    vitamin K1;   

DOI  :  10.1016/0014-5793(91)80771-T

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Room temperature transient EPR spectra of photosystem I (PS I) particles from Synechocystis 6803 are presented. Native PS I samples and preparations depleted in the A₁-acceptor site by solvent extraction and then reconstituted with the quinones (Q) vitamin K₁ (VK₁), duroquinone (DQ and DQd₁₂) and naphthoquinone (NQ) have been studied. Sequential electron transfer to P⁺ ₇₀₀A⁻ ₁ (FeS) and P⁺ ₇₀₀A₁ (FeS)⁻ is recovered only with VK₁. With DQ and NQ electron transfer is restored to form the radical pair P⁺ ₇₀₀Q⁻ as specified by a characteristic electron spin polarization (ESP)-pattern, but further electron transfer is either slowed down or blocked. A qualitative analysis of the K-band spectrum suggests that the orientation of reconstituted NQ in PS I is different from the native acceptor A₁ = VK₁.

【 授权许可】

Unknown