Nearest-neighbor analysis of higher-plant photosystem I holocomplex
Nearest-neighbor analysis of higher-plant photosystem I holocomplex
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DOI：
10.1104/pp.112.1.409
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发表时间：
1996-09-01
期刊：
影响因子：
7.4
通讯作者：
Scheller, HV
中科院分区：
文献类型：
--
作者：
Jansson, S;Andersen, B;Scheller, HV
用可裂解的同型双功能交联剂二硫代双（琥珀酰亚胺基丙酸酯）和3，3 '-二硫代双（磺基琥珀酰亚胺基丙酸酯）对大麦（Hordeum vulgare）和菠菜（Spinacia oleracea）的光系统I（PSI）制剂进行化学交联。通过简单但功能强大的对角电泳技术和免疫印迹分析交联产物的总体模式，其中交联剂中的二硫键在凝胶的第一和第二维之间裂解。大量的交联产物被确定。结合已有的PSI结构数据，推断出亚基PSI-D、PSI-H、PSI-I和PSI-L占据复合物的一侧，而PSI-E、PSI-F和PSI-J占据另一侧。PSI-K和PSI-G似乎分别与Lhca 3和Lhca 2相邻，而不靠近其他小亚基。用分离的捕光复合物制备物进行的实验表明，亚基被组织为二聚体，其似乎与PSI-A/PSI-B蛋白相互独立地缔合。我们建议PSI亚基对应于蓝藻PSI结构中的每个跨膜螺旋，并提出了高等植物PSI的模型。
Photosystem I (PSI) preparations from barley (Hordeum vulgare) and spinach (Spinacia oleracea) were subjected to chemical crosslinking using the cleavable homobifunctional cross-linkers dithiobis(succinimidylpropionate) and 3,3'-dithiobis(sulfosuccinimidylpropionate). The overall pattern of cross-linked products was analyzed by the simple but powerful technique of diagonal electrophoresis, in which the disulfide bond in the cross-linker was cleaved between the first and second dimensions of the gel, and immunoblotting. A large number of cross-linked products were identified. Together with preexisting data on the structure of PSI, it was deduced that the subunits PSI-D, PSI-H, PSI-I, and PSI-L occupy one side of the complex, whereas PSI-E, PSI-F, and PSI-J occupy the other. PSI-K and PSI-G appear to be adjacent to Lhca3 and Lhca2, respectively, and not close to the other small subunits. Experiments with isolated light-harvesting complex ] preparations indicate that the subunits are organized as dimers, which seem to associate to the PSI-A/PSI-B proteins independent of each other. We suggest which PSI subunit corresponds to each membrane-spanning helix in the cyanobacterial PSI structure, and present a model for higher-plant PSI.