摘要
光系统Ⅱ（ＰＳⅡ）反应中心Ｄ１／Ｄ２／Ｃｙｔｂ－５５９ 复合物在４８８ ｎｍ 处激发的共振拉曼光谱显示４ 个主要谱带，其峰位分别在１５３２（υ１）、１１６５（υ２）、１０１０（υ３）和９７０（υ４） ｃｍ － １处，表明ＰＳⅡ反应中心结合的β－胡萝卜素分子是全反式构型。Ｄ１／Ｄ２／Ｃｙｔｂ－５５９ 复合物的色素抽提液的拉曼光谱也显示４ 个主要的拉曼峰，其中υ４ 谱带的强度急剧下降，说明ＰＳⅡ反应中心内部结合的β－胡萝卜素分子与抽提液中自由的β－胡萝卜素分子的构象不同，而与光合细菌反应中心内部的类胡萝卜素分子的构象相似。
The resonance Raman spectrum of β carotene in photosystem Ⅱ(PSⅡ)reaction center complex was characterized by four main bands, peaking at 1532(υ1), 1156(υ2), 1010(υ3)and 970(υ4)cm -1 , respectively, with several additional small Raman bands in the region between 1100 cm -1 and 1500 cm -1 .It was suggested that β carotene molecules of the reaction center complex were in all trans configuration.The resonance Raman spectrum of an acetone extract from the reaction center complex also showed four main bands.The peak position of υ1, υ3 and υ4 band shifted 5 cm -1 to the shorter wave number.The most dramatic changes were the reduction of the intensity of υ4.From the above results it was demonstrated that the conformation of β carotene molecules in the PS Ⅱreaction center was not the same as that of free β carotene molecules in solution, but similar to that of carotenoid molecules in the photosynthetic bacterial reaction center, in other words, they are likely to be in a twisted conformation.
