紫细菌光合反应中心中细菌脱镁叶绿素被置换后的光化学活性  

The Photochemical Change in Photosynthetic Reaction Center of Purple Bacterium with Pheophytin Substitution

作　　者：曾小华[1,2] 徐春和 吴永强[1,2] 刘先年 沈允钢[1,2] 

机构地区：[1]中国科学院上海植物生理研究所 [2]复旦大学激光化学研究所

出　　处：《生物化学与生物物理学报》1999年第3期337-340,共4页

基　　金：国家自然科学基金;国家重点基础研究发展规划资助项目

摘　　要：采用新型表面活性剂ＬＤＡＯ，结合ＤＥＡＥ纤维素层析法，我们提纯了紫细菌Ｒｈｏｄｏｂａｃｔｅｒｓｐｈａｅｒｏｉｄｅｓ６０１的光合反应中心。在一定温度和丙酮的协同作用下，外加的植物脱镁叶绿素ａ可取代反应中心细菌脱镁叶绿素，形成含有脱镁叶绿素ａ的紫细菌光合反应中心（ＰｈｅａＲＣ）。当协同作用１５ｍｉｎ和６０ｍｉｎ时，反应中心中的细菌脱镁叶绿素分别被替代了５０％和７１％。在ＰｈｅａＲＣ中，细菌脱镁叶绿素的ＱＸ（５３７ｎｍ）和ＱＹ（７５８ｎｍ）特征峰显著下降，而出现高等植物脱镁叶绿素的ＱＸ（５０９／５４２ｎｍ）和ＱＹ（６７４ｎｍ）特征峰。排除温度和丙酮的影响，替代时间为１５ｍｉｎ或６０ｍｉｎ的ＰｈｅａＲＣ的光化学活性分别为对照的７８％或７１％。The reaction centers are isolated from chromatophores of Rhodobacter sphaeroides 601 by detergent LDAO, and purified by chromatography on a DEAE 52 cellulose column. In the presence of acetone and an access of free pheophytins (Phes), bacteriopheophytins (Bphes) in reaction centers are replaced by pheophytins at sites H A and H B when incubated under high temperature. The substituting amounts are about 50% and 71% Bphes in reaction centers with incubation of fifteen and sixty minutes respectively. In the absorption spectra of reaction centers containing Phes (Phe RC), the Q X(537 nm)and Q Y(758 nm)bands of Bphe disappeared, three distinct bands assigned to the Q X(509/542 nm)and Q Y(674 nm)bands of phe appeared. Compared to reaction centers in control, the photochemical activities of Phe RCs, with incubating time of fifteen and sixty minutes, drop to 78% and 71% of that in control respectively。

关 键 词：紫细菌 光合反应中心 脱镁叶绿素 光化学活性 

分 类 号：Q936[生物学—微生物学]