Koller K P, Wehrmeyer W, Mörschel E
Eur J Biochem. 1978 Nov 2;91(1):57-63. doi: 10.1111/j.1432-1033.1978.tb20936.x.
Heterogeneous complexes with a molecular weight of about 790000 containing B-phycoerythrin (Bangiales phycoerythrin) and C-phycocyanin (Cyanophyceae phycocyanin) in a molar pigment ratio of 2:1 were isolated from purified, dissociated phycobilisomes. Electron microscopical investigations revealed structures of three discs aggregated face to face with an apparent distance of 1.5 nm between each disc. Two discs may represent phycoerythrin and one phycocyanin. The complexes are structurally identical with tripartite units of the phycobilisome periphery. Fluorescence data confirmed the integrity of isolated tripartite units. Excitation at 546 nm gives a fluorescence maximum at 644 nm, indicating intermolecular transfer of excitation energy from phycoerythrin to phycocyanin. Comparative subunit analyses and spectral data suggested that no allophycocyanin is present. Cross-linking experiments gave evidence for a polar arrangement of phycocyanin within the complex. This pigment itself is an aggregate of two smaller molecules each having a molecular weight of about 140000. Tripartite units contain all the phycoerythrin and phycocyanin of the phycobilisome. On this basis, a phycobilisome model is proposed which combines the aspects of biliprotein distribution, energy transfer and fine structure.
从纯化的、解离的藻胆体中分离出了分子量约为790000的异质复合物，其含有B-藻红蛋白（红毛菜纲藻红蛋白）和C-藻蓝蛋白（蓝藻纲藻蓝蛋白），色素摩尔比为2:1。电子显微镜研究揭示了三个圆盘面对面聚集的结构，每个圆盘之间的表观距离为1.5纳米。两个圆盘可能代表藻红蛋白，一个代表藻蓝蛋白。这些复合物在结构上与藻胆体周边的三方单元相同。荧光数据证实了分离出的三方单元的完整性。在546纳米处激发，在644纳米处产生荧光最大值，表明激发能量从藻红蛋白向藻蓝蛋白的分子间转移。比较亚基分析和光谱数据表明不存在别藻蓝蛋白。交联实验证明了藻蓝蛋白在复合物中的极性排列。这种色素本身是两个分子量约为140000的较小分子的聚集体。三方单元包含藻胆体的所有藻红蛋白和藻蓝蛋白。在此基础上，提出了一个藻胆体模型，该模型结合了双蛋白分布、能量转移和精细结构等方面。
