Influence of the H‐subunit and Fe2+ on electron transport from I− to QA in Fe2+‐free and/or H‐free reaction centers from Rhodobacter sphaeroides R‐26

FEBS Letters

Liu, Ben-li¹  Hoff, Arnold J.¹  van Kan, Paul J.M.¹ 

[1] Department of Biophysics, Huygens Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands

关键词: Reaction center;    Quinone;    Electron transport;    Transition metal;    H-subunit;    Kinetics;    Depletion;    Reconstitution;    Rhodobacter sphaeroides;    QA and QB;    primary and secondary electron acceptors;    Vitamin K1;    2-methyl-3-phytyl-1;    4-naphthoquinone;    UQ;    ubiquinone;    Bchl a;    bacteriochlorophyll a;    Bph a;    bacteriopheophytin a;    LDAO;    lauryldimethylamine N-oxide;    EDTA;    ethylenediaminetetraacetic acid;    SDS-PAGE;    sodium dodecyl sulphate polyacrylamide gel electrophoresis;   

DOI  :  10.1016/0014-5793(91)80900-N

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

From reaction centres (RC) of Rhodobacter sphaeroides R-26 two LM preparations with 0.90 Fe²⁺/RC (LM) and 0.10 Fe²⁺/RC (LM/dFe) were prepared. Reconstitution of LM/dFe with the H-subunit and subsequently with Zn²⁺ yielded LMH/dFe and LMH/dFe+Zn preparations, respectively. In these four samples the decay of the primary radical pair P⁺I⁻ was studied by means of transient absorption spectroscopy and compared with that in native RC. In LMH/dFe the reduction of Q_A by Bpheo a occurred in 5 ns, with concomitant increase in the yield of P^T, the triplet state of the primary donor. In the LM/dFe, LM and LMH/dFe+Zn preparations the decay of I⁻ had the same rate (200 ps)⁻¹ as in native RC. Thus, neither the H-subunit in the RC nor a divalent metal as Fe²⁺ or Zn²⁺ are necessary per se for fast reduction of Q_A. Only demetallation in the presence of the H-subunit slows down the reduction of Q_A.

【 授权许可】

Unknown