The structure of Photosystem I acclimated to far-red light illuminates an ecologically important acclimation process in photosynthesis
The structure of Photosystem I acclimated to far-red light illuminates an ecologically important acclimation process in photosynthesis
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DOI：
10.1126/sciadv.aay6415
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发表时间：
2020-02-01
期刊：
影响因子：
13.6
通讯作者：
Bryant, Donald A.
中科院分区：
文献类型：
--
作者：
Gisriel, Christopher;Shen, Gaozhong;Bryant, Donald A.
光养生物能很好地适应不同的光环境，但通常必须适应其生态位中可见光波长的竞争。一些蓝藻通过表达旁系光合蛋白和合成并将类似8%的叶绿素f合并到它们的光系统I （PSI）复合体中来克服这一挑战，使它们能够在远红光（FRL）下生长。本文采用单粒子低温电镜技术，分析了来自热菲氏蓝藻PCC 7521经frl驯化后的PSI的结构，了解其结构和功能差异。提出了叶绿素f占据的四个结合位点。微妙的结构变化使frl适应的PSI能够将氧气光合作用的光利用率扩展到近800 nm。该结构为理解frl驱动的光合作用提供了一个平台，并说明了自然界中适应性和驯化机制的稳健性。
Phototrophic organisms are superbly adapted to different light environments but often must acclimate to challenging competition for visible light wavelengths in their niches. Some cyanobacteria overcome this challenge by expressing paralogous photosynthetic proteins and by synthesizing and incorporating similar to 8% chlorophyll f into their Photosystem I (PSI) complexes, enabling them to grow under far-red light (FRL). We solved the structure of FRL-acclimated PSI from the cyanobacterium Fischerella thermalis PCC 7521 by single-particle, cryo-electron microscopy to understand its structural and functional differences. Four binding sites occupied by chlorophyll f are proposed. Subtle structural changes enable FRL-adapted PSI to extend light utilization for oxygenic photosynthesis to nearly 800 nm. This structure provides a platform for understanding FRL-driven photosynthesis and illustrates the robustness of adaptive and acclimation mechanisms in nature.