蓝隐藻色素蛋白复合物的分离和分析

Isolation and Characterization of Pigment-protein Complexes of Chroomonas placoidea

分别采用等电点聚焦(IEF)和聚丙烯酰胺凝胶电泳(PAGE)方法分离蓝隐藻(Chro-om onas placoidea)类囊体膜色素蛋白复合物.经IEF分离得到5条带,依迁移距离从小到大命名为带Ⅰ(黄绿色,叶绿素蛋白复合物)、带Ⅱ(桔红色,类胡萝卜素-蛋白复合物)、带Ⅲ-Ⅴ(蓝色,隐藻藻蓝蛋白),其等电点分别为pH 4.5、4.7、5.2、5.4和5.9.经PAGE分离最多得到4条色素蛋白带,分别为PSI中心复合物CPI和PSI复合物颗粒CPIa以及2个特异的藻蓝蛋白(PC)-Chl a/c-捕光蛋白复合物.值得注意的是,给予580、460和435 nm的激发光,捕光复合物都可发射680-682 nm Chl a的荧光.这一结果表明,蓝隐藻中藻胆蛋白与捕光叶绿素蛋白的是紧密结合存在的,并且具有能量传递关系.

Pigment-protein complexes of Chroomonas placoidea thylakoids are separated by IEF and PAGE. Five bands are resolved by IEF, named as Band Ⅰ （ yellowish green, chlorophyll-protein complex）, Band Ⅱ （ orange, xanthophyll-protein complex） and Band Ⅲ-Ⅴ （ blue, crypto- phycocyanin） according to their migration distance. Their isoelelectric points are around 4. 5, 4. 7,5.2,5.4 and 5.9, respectively. Four pigment-protein complexes which are PSI complex CPI and CPIa, and two novel phycocyanin-Chl a/c-protein light-harvesting complexes are separated by PAGE methods. It is noticeable that the light-harvesting complexes emit at 680-682 nm fluorescence of Chl a when excited at 580 nm, 460 nm and 435 nm, indicating that phycobiliproteins in C. placoidea are closely associated with light-harvesting chlorophyll-protein complexes and there exists an efficient energy transfer relationship.