Oren-Shamir M, Sai P S, Edelman M, Scherz A
Department of Biochemistry, Weizmann Institute of Science, Rehovot, Israel.
Biochemistry. 1995 Apr 25;34(16):5523-6. doi: 10.1021/bi00016a025.
A chlorophyll-protein complex has been isolated from the cyanobacterium Synechocystis sp. PCC 6803 that closely resembles higher plant photosystem II reaction centers in spectral properties. The Synechocystis complex has a pigment content of 5-7 chlorophyll a molecules:1 Cyt b559:2 pheophytins; an optical absorption redmost transition at approximately 675 nm; and a nonconservative circular dichroism red signal, with extrema at 682 (+) and 652 (-) nm. Upon illumination, the Synechocystis D1/D2/Cyt b559 complex accumulates reduced pheophytin. LDS-PAGE and/or immunoblotting showed the D1, D2, and Cyt b559 proteins, aggregated and degraded forms of D1 and possibly D2, and traces of ATP synthase and the CP47 photosystem II chlorophyll protein. The availability of such a Synechocystis preparation opens the way for employing site-directed mutagenesis in studying primary reactions of oxygenic photosynthesis.
已从集胞藻属蓝细菌PCC 6803中分离出一种叶绿素-蛋白质复合物，其光谱特性与高等植物光系统II反应中心极为相似。集胞藻复合物的色素含量为5 - 7个叶绿素a分子：1个细胞色素b559：2个脱镁叶绿素；在约675 nm处有一个光学吸收最红移跃迁；以及一个非保守的圆二色性红色信号，其极值在682（+）和652（-）nm处。光照后，集胞藻D1/D2/细胞色素b559复合物积累还原型脱镁叶绿素。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳和/或免疫印迹显示了D1、D2和细胞色素b559蛋白、D1和可能的D2的聚集和降解形式，以及痕量的ATP合酶和CP47光系统II叶绿素蛋白。这种集胞藻制剂的可得性为在研究光合放氧的初级反应中采用定点诱变开辟了道路。
