Wynn R M, Bertsch J, Bruce B D, Malkin R
Division of Molecular Plant Biology, University of California, Berkeley 94720.
Biochim Biophys Acta. 1988 Sep 14;935(2):115-22. doi: 10.1016/0005-2728(88)90208-3.
Cytochrome b6-f complexes have been isolated from Chlamydomonas reinhardtii, Dunaliella saline and Scenedesmus obliquus. Each complex is essentially free of chlorophyll and carotenoids and contains cytochrome b6 and cytochrome f hemes in a 2:1 molar ratio. C. reinhardtii and S. obliquus complexes contain the Rieske iron-sulfur protein (present in approx 1:1 molar ratio to cytochrome f) and each catalyzes a DBMIB- and DNP-INT-sensitive electron transfer from duroquinol to spinach plastocyanin. Immunological assays using antibodies to the peptides from the spinach cytochrome complex show varying cross-reactivity patterns except for the complete absence of binding to the Rieske proteins in any of the three complexes, suggesting little structural similarity between the Rieske proteins of algae with those from higher plants. One complex (D. salina) has been uniformly labeled by growth in NaH14CO3 to determine stoichiometries of constituent polypeptide subunits. Results from these studies indicate that all functionally active cytochrome b6-f complexes contain four subunits which occur in equimolar amounts.
细胞色素b6-f复合物已从莱茵衣藻、盐生杜氏藻和斜生栅藻中分离出来。每个复合物基本上不含叶绿素和类胡萝卜素，并且含有细胞色素b6和细胞色素f血红素，其摩尔比为2:1。莱茵衣藻和斜生栅藻复合物含有铁硫蛋白（与细胞色素f的摩尔比约为1:1），并且各自催化从杜醌醇到菠菜质体蓝素的对二溴甲基异喹啉（DBMIB）和二硝基苯基异烟肼（DNP-INT）敏感的电子转移。使用针对菠菜细胞色素复合物肽段的抗体进行的免疫测定显示出不同的交叉反应模式，但在这三种复合物中的任何一种中都完全不存在与铁硫蛋白的结合，这表明藻类的铁硫蛋白与高等植物的铁硫蛋白之间几乎没有结构相似性。一种复合物（盐生杜氏藻）通过在NaH14CO3中生长进行均匀标记，以确定组成多肽亚基的化学计量。这些研究结果表明，所有功能活性的细胞色素b6-f复合物都含有四个等摩尔量的亚基。
