Functional LH1 antenna complexes influence electron transfer in bacterial photosynthetic reaction centers

被引:0
作者
Ronald W. Visschers
Simone I.E. Vulto
Michael R. Jones
Rienk van Grondelle
Ruud Kraayenhof
机构
[1] Institute of Molecular Biological Sciences,Department of Structural Biology, BioCentrum Amsterdam
[2] Institute of Molecular Biological Sciences,Department of Biophysics, BioCentrum Amsterdam
[3] University of Sheffield,Krebs Institute for Biomolecular Research and Robert Hill Institute for Photosynthesis, Department of Molecular Biology and Biotechnology
来源
Photosynthesis Research | 1999年 / 59卷
关键词
bacteriochlorophyll a; electron transfer; light harvesting; photosynthesis; Rhodobacter sphaeroides; reaction center;
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学科分类号
摘要
The effect of the light harvesting 1 (LH1) antenna complex on the driving force for light-driven electron transfer in the Rhodobacter sphaeroides reaction center has been examined. Equilibrium redox titrations show that the presence of the LH1 antenna complex influences the free energy change for the primary electron transfer reaction through an effect on the reduction potential of the primary donor. A lowering of the redox potential of the primary donor due to the presence of the core antenna is consistently observed in a series of reaction center mutants in which the reduction potential of the primary donor was varied over a 130 mV range. Estimates of the magnitude of the change in driving force for charge separation from time-resolved delayed fluorescence measurements in the mutant reaction centers suggest that the mutations exert their effect on the driving force largely through an influence on the redox properties of the primary donor. The results demonstrate that the energetics of light-driven electron transfer in reaction centers are sensitive to the environment of the complex, and provide indirect evidence that the kinetics of electron transfer are modulated by the presence of the LH1 antenna complexes that surround the reaction center in the natural membrane.
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页码:95 / 104
页数:9
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