A laser flash absorption spectroscopy study of Anabaena sp. PCC 7119 flavodoxin photoreduction by photosystem I particles from spinach

FEBS Letters

De la Rosa, Miguel A.³  Gómez-Moreno, Carlos¹  Medina, Milagros¹  Tollin, Gordon²  Hervás, Manuel³  Navarro, José A.³ 

[1] Departamento de Bioquimica y Biologia Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, 50009-Zaragoza, Spain;Department of Biochemistry, University of Arizona, Tucson, AZ 85721, USA;Instituto de Bioquimica Vegetal y Fotosintesis, Universidad de Sevilla y CSIC, Apartado 1113, 41080-Sevilla, Spain

关键词: Flavodoxin;    Photosystem I;    Electron transfer;    DCPIP;    dichlorophenolindophenol;    Fld;    flavodoxin;    Fd;    ferredoxin;    FMN;    flavin mononucleotide;    FNR;    ferredoxin-NADP+ reductase;    PSI;    photosystem I;    TSF-1;    Triton-solubilized PSI particles;    k obs;    observed rate constants;   

DOI  :  10.1016/0014-5793(92)81200-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Electron transfer from P700 in photosystem I (PSI) particles from spinach to Anabaena sp. PCC 7119 flavodoxin has been studied using laser flash absorption spectroscopy. A non-linear protein concentration dependence of the rate constants was obtained, suggesting a two-step mechanism involving complex formation (k=3.6 × 10⁷ M⁻¹· s⁻¹) followed by intracomplex electron transfer (k=270 s⁻¹). The observed rate constants had a biphasic dependence on the concentrations of NaCl or MgCl₂ with maximum values in the 40–80 mM range for NaCl and 4–12 mM for MgCl₂. To our knowledge, this is the first time that the kinetics of PSI-dependent flavodoxin photoreduction have been determined.

【 授权许可】

Unknown