Tuning of the redox potential of the primary electron donor in reaction centres of purple bacteria: effects of amino acid polarity and position

FEBS Letters

Jones, Michael R³  Spiedel, Diane¹  Robert, Bruno² 

[1] Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2UH, UK;Section de Biophysique des Fonctions Membranaires, DBJC/CEA and URA 2096 CNRS, C.E.A. Saclay, 91191 Gif/Yvette, France;Department of Biochemistry, School of Medical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK

关键词: Reaction centre;    Photosynthesis;    Redox potential;    Bacteriochlorophyll;    Permanent dipole;    Charge–dipole interaction;    BChl;    bacteriochlorophyll;    ΔSPD;    change in side-chain permanent dipole;    P;    primary donor of electrons;    P+;    primary donor cation;   

DOI  :  10.1016/S0014-5793(02)03203-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Mutation of residues His L168 and Phe M197 in the reaction centre from Rhodobacter sphaeroides has an unusually strong effect on the mid-point redox potential (E _m) of the pair of bacteriochlorophylls that form the primary donor of electrons, tuning E _m over a range of nearly 250 mV. This effect is correlated to the accompanying change in the permanent dipole of the L168 or M197 residue, suggesting it is mediated by changes in charge–dipole interactions. Comparisons with mutations made at a variety of other positions show that this correlation is particular to this residue pair, perhaps reflecting their proximity to the ring I regions of the dimer bacteriochlorophylls that form the overlap region between these molecules.

【 授权许可】

Unknown