Arellano Juan B, González-Pérez Sergio, Vacha Frantisek, Melø Thor Bernt, Naqvi K Razi
Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim, Norway.
Biochemistry. 2007 Dec 25;46(51):15027-32. doi: 10.1021/bi701440z. Epub 2007 Dec 4.
A pigment-deficient reaction center of photosystem II (PSII)-with all the core pigments (two molecules of chlorophyll a and one of pheophytin a in each D protein) but with only one molecule each of peripheral chlorophyll a (Chlz) and beta-carotene (Car)-has been investigated by pump-probe spectroscopy. The data imply that Car and Chlz are both bound to D1. The absence of Car and Chlz in D2 allows the unprecedented observation of secondary electron transfer in D1 of PSII reaction centers at room temperature. The absorption band of the Car cation in D1 (Car(D1)(+)) peaks around 910 nm (as against 990 nm for Car(D2)(+)), and its positive hole is shared by ChlzD1, whereas Car(D2)(+*) can disappear by capturing an electron from ChlzD2.
利用泵浦-探测光谱对光合系统II（PSII）中一个色素缺乏的反应中心进行了研究，该反应中心含有所有核心色素（每个D蛋白中有两个叶绿素a分子和一个脱镁叶绿素a分子），但每个仅含有一个外周叶绿素a（Chlz）分子和β-胡萝卜素（Car）分子。数据表明，Car和Chlz都与D1结合。D2中不存在Car和Chlz，这使得在室温下对PSII反应中心D1中的二次电子转移进行了前所未有的观测。D1中Car阳离子（Car(D1)(+)）的吸收带在910 nm左右达到峰值（而Car(D2)(+)为990 nm），其正电荷空穴由ChlzD1共享，而Car(D2)(+*)可以通过从ChlzD2捕获一个电子而消失。
