X-ray structure of an asymmetrical trimeric ferredoxin-photosystem I complex
X-ray structure of an asymmetrical trimeric ferredoxin-photosystem I complex
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DOI：
10.1038/s41477-018-0130-0
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发表时间：
2018-04-01
期刊：
影响因子：
18
通讯作者：
Kurisu, Genji
中科院分区：
文献类型：
--
作者：
Kubota-Kawai, Hisako;Mutoh, Risa;Kurisu, Genji
光系统I（PSI）是位于类囊体膜中的一种大型蛋白质复合物，介导光驱动电子转移到基质电子载体蛋白铁氧还蛋白（Fd）的最后一步。在这里，我们报告的PSI-Fd复杂的细长热聚球藻的第一个结构描述。三聚体PSI复合物以非等效方式结合三个Fd。虽然每一个都被PSI原聚体以相似的方向识别，但Fds和PSI氧化还原中心之间的距离不同。因此，Fd结合导致PSI可溶性亚基的精确三重对称性丧失，诱导通过PsaF转移到管腔的结构扰动。PSI-Fd复合物的亲和色谱和核磁共振分析支持存在两种不同的Fd结合状态，其中一种Fd比其他结合更紧密。我们提出了一个动态的结构基础生产复杂的形成，这支持PSI和FD之间的快速电子转移。
Photosystem I (PSI), a large protein complex located in the thylakoid membrane, mediates the final step in light-driven electron transfer to the stromal electron carrier protein ferredoxin (Fd). Here, we report the first structural description of the PSI-Fd complex from Thermosynechococcus elongatus. The trimeric PSI complex binds three Fds in a non-equivalent manner. While each is recognized by a PSI protomer in a similar orientation, the distances between Fds and the PSI redox centres differ. Fd binding thus entails loss of the exact three-fold symmetry of the PSI's soluble subunits, inducing structural perturbations which are transferred to the lumen through PsaF. Affinity chromatography and nuclear magnetic resonance analyses of PSI-Fd complexes support the existence of two different Fd-binding states, with one Fd being more tightly bound than the others. We propose a dynamic structural basis for productive complex formation, which supports fast electron transfer between PSI and Fd.