Energy and electron transfer in the photosynthetic reaction center complex of Acidiphilium rubrum containing Zn-bacteriochlorophyll a studied by femtosecond up-conversion spectroscopy.
Energy and electron transfer in the photosynthetic reaction center complex of Acidiphilium rubrum containing Zn-bacteriochlorophyll a studied by femtosecond up-conversion spectroscopy.
复制标题
DOI：
10.1016/j.bbabio.2006.10.008
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
T. Tomi;Y. Shibata;Y. Ikeda;S. Taniguchi;Chosrowjan Haik;N. Mataga;K. Shimada;S. Itoh
中科院分区：
文献类型：
--
作者：
T. Tomi;Y. Shibata;Y. Ikeda;S. Taniguchi;Chosrowjan Haik;N. Mataga;K. Shimada;S. Itoh
从一株紫色细菌红色嗜酸菌（Acidiphilium rubrum）中分离到一个光合反应中心复合体。RC含有含有Zn作为中心金属的细菌叶绿素a（Zn-BChl a）和细菌脱镁叶绿素a（BPhe a），但不含Mg-BChl a。在RC中，Zn-BChl a二聚体（PZn）、辅助Zn-BChl a（BZn）和BPhe a（H）在4K下的吸收峰分别显示在875、792和753 nm处。这些峰短于具有Mg-BChla的类球形红细菌RC中的相应峰。从PZn* 的荧光动力学，通过荧光上转换测量，显示上升和主要衰减的时间常数分别为0.16和3.3 ps。前者代表BZn ~* 向PZn的能量转移，后者代表PZn向H的电子转移。根据荧光各向异性，估算出BZn和PZn的跃迁偶极子之间的夹角为36°。时间常数和角度几乎等于Rb中的时间常数和角度。球形RC。A.红色RC似乎通过Zn-BChla的化学性质和通过修饰PZn的RC蛋白的L168 HE修饰而实现。
A photosynthetic reaction center (RC) complex was isolated from a purple bacterium, Acidiphilium rubrum. The RC contains bacteriochlorophyll a containing Zn as a central metal (Zn-BChl a) and bacteriopheophytin a (BPhe a) but no Mg-BChl a. The absorption peaks of the Zn-BChl a dimer (PZn), the accessory Zn-BChl a (BZn), and BPhe a (H) at 4 K in the RC showed peaks at 875, 792, and 753 nm, respectively. These peaks were shorter than the corresponding peaks in Rhodobacter sphaeroides RC that has Mg-BChl a. The kinetics of fluorescence from PZn*, measured by fluorescence up-conversion, showed the rise and the major decay with time constants of 0.16 and 3.3 ps, respectively. The former represents the energy transfer from BZn*to PZn, and the latter, the electron transfer from PZnto H. The angle between the transition dipoles of BZnand PZnwas estimated to be 36° based on the fluorescence anisotropy. The time constants and the angle are almost equal to those in the Rb. sphaeroides RC. The high efficiency of A. rubrum RC seems to be enabled by the chemical property of Zn-BChl a and by the L168HE modification of the RC protein that modifies PZn.