Department of Chemistry, University of Southern California, Los Angeles, California 90007.
Proc Natl Acad Sci U S A. 1980 Jun;77(6):3105-9. doi: 10.1073/pnas.77.6.3105.
The role of a special dimer (D) of bacteriochlorophyll molecules in bacterial photosynthesis was examined by calculations of the rates of electron transfer reactions in a system of the dimer and a bacteriopheophytin (BPh) molecule. It was found that the dependence of the potential surfaces of D on the distance between the monomers allows a fast light-induced electron transfer from D to BPh but only a slow back reaction (reduction of D(+) by BPh(-)). The same potential surfaces allow efficient reduction of D(+) by cytochrome c. Possible advantages of greatly different values of the electronic matrix elements for the forward and back reactions are pointed out. It is suggested that the electrostatic interaction between D(+) and an ionized group of the protein might play an important role in the photosynthetic reaction.
通过计算二聚体(D)和细菌叶绿素(BPh)分子系统中的电子转移反应速率,研究了细菌光合作用中二聚体特殊二聚体(D)的作用。结果发现,D 的势能面与单体之间的距离的依赖性允许 D 到 BPh 的快速光诱导电子转移,但只有缓慢的反向反应(BPh(-)还原 D(+))。相同的势能面允许 D(+)被细胞色素 c 有效还原。指出了前向和后向反应的电子矩阵元素值差异很大的可能优势。有人建议,D(+)与蛋白质的离子基团之间的静电相互作用可能在光合作用反应中起重要作用。