Electrometrical study of electron transfer from the terminal FA/FB iron–sulfur clusters to external acceptors in photosystem I

FEBS Letters

Mamedov, Mahir D.¹  Mamedova, Aygun A.¹  Vassiliev, Ilya R.²  Semenov, Alexey Yu.¹  Gourovskaya, Kira N.¹  Golbeck, John H.² 

[1]Department of Photobiochemistry, A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119899 Moscow, Russia

[2]Department of Biochemistry and Molecular Biology, The Pennsylvania State University, S-310 Frear Laboratory, University Park, PA 16802-4500, USA

关键词: Photosystem I;    Electron transfer;    Proteoliposome;    Electrogenic reaction;    Fe–S center;    Flavodoxin;    Ferredoxin;    Methyl viologen;    Synechococcus sp. PCC 6301;    PS I;    photosystem I;    FX;    FA;    FB;    iron–sulfur clusters of photosystem I;    P700;    primary donor of photosystem I;    MV;    methyl viologen;    DCPIP;    2;    6-dichlorophenolindophenol;    ΔΨ;    transmembrane electric potential difference;    τ;    characteristic time constant;   

DOI  :  10.1016/S0014-5793(99)01570-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

An electrometrical technique was used to investigate electron transfer between the terminal iron–sulfur centers F_A/F_B and external electron acceptors in photosystem I (PS I) complexes from the cyanobacterium Synechococcus sp. PCC 6301 and from spinach. The increase of the relative contribution of the slow components of the membrane potential decay kinetics in the presence of both native (ferredoxin, flavodoxin) and artificial (methyl viologen) electron acceptors indicate the effective interaction between the terminal [4Fe–4S] cluster and acceptors. The finding that F_A fails to donate electrons to flavodoxin in F_B-less (HgCl₂-treated) PS I complexes suggests that F_B is the direct electron donor to flavodoxin. The lack of additional electrogenicity under conditions of effective electron transfer from the F_B redox center to soluble acceptors indicates that this reaction is electrically silent.

【 授权许可】

Unknown