Flash‐induced electrogenic reactions in the SA(L223) reaction center mutant in Rhodobacter sphaeroides chromatophores

FEBS Letters

Bloch, Dmitry A.³  Semenov, Alexey Yu.³  Cherepanov, Dmitry A.²  Oesterhelt, Dieter¹  Bibikov, Sergei I.³ 

[1] Max-Plank-Institut für Biochemie, München, Germany;Institute of Electrochemistry, Russian Academy of Sciences, Moscow, Russian Federation;A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119899 Moscow, Russian Federation

关键词: Bacterial chromatophore;    Reaction center complex;    Electrogenic reaction;    Ubiquinone;    Site-specific mutation;    Rhodobacter sphaeroides;   

DOI  :  10.1016/0014-5793(94)80230-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The charge transfer events in the SA(L223) reaction center mutant Rhodobacter sphaeroides chromatophores were investigated by direct electrometry. Besides the primary charge separation, the small stigmatellin-sensitive electrogenic reaction due to the electron transfer from the primary to the secondary quinone acceptor in the reaction center complex was observed after the first flash. The second flash-induced electrogenic phase of the secondary quinone protonation and subsequent electrogenic reactions of the cytochrome bc ₁ complex were much slower than those in chromatophores of the wild type. It is suggested that replacement of Ser-L223 by Ala impairs both specific proton-conducting pathways leading to the secondary quinone Q_B.

【 授权许可】

Unknown