Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan.
Faculty of Science, Tokyo University of Science, Tokyo, 162-8601, Japan.
Nat Commun. 2020 Jan 13;11(1):238. doi: 10.1038/s41467-019-13898-5.
Chlorophylls (Chl) play pivotal roles in energy capture, transfer and charge separation in photosynthesis. Among Chls functioning in oxygenic photosynthesis, Chl f is the most red-shifted type first found in a cyanobacterium Halomicronema hongdechloris. The location and function of Chl f in photosystems are not clear. Here we analyzed the high-resolution structures of photosystem I (PSI) core from H. hongdechloris grown under white or far-red light by cryo-electron microscopy. The structure showed that, far-red PSI binds 83 Chl a and 7 Chl f, and Chl f are associated at the periphery of PSI but not in the electron transfer chain. The appearance of Chl f is well correlated with the expression of PSI genes induced under far-red light. These results indicate that Chl f functions to harvest the far-red light and enhance uphill energy transfer, and changes in the gene sequences are essential for the binding of Chl f.
叶绿素（Chl）在光合作用中发挥着能量捕获、转移和电荷分离的关键作用。在进行产氧光合作用的叶绿素中，Chl f 是最早在蓝细菌 Halomicronema hongdechloris 中发现的最红移类型。Chl f 在光系统中的位置和功能尚不清楚。在这里，我们通过冷冻电镜分析了在白光或远红光下生长的 H. hongdechloris 中 PSI 核心的高分辨率结构。该结构表明，远红光 PSI 结合了 83 个 Chl a 和 7 个 Chl f，Chl f 位于 PSI 的外围，但不在电子传递链中。Chl f 的出现与远红光诱导的 PSI 基因表达密切相关。这些结果表明，Chl f 的功能是吸收远红光并增强 uphill 能量转移，基因序列的变化对于 Chl f 的结合至关重要。
Zotero 插件
