Antenna arrangement and energy transfer pathways of a green algal photosystem I-LHCI supercomplex
Antenna arrangement and energy transfer pathways of a green algal photosystem I-LHCI supercomplex
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绿藻光系统-I-LHCI超复合体的天线排列和能量传递途径
DOI：
10.1038/s41477-019-0380-5
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发表时间：
2019
期刊：
影响因子：
18
通讯作者：
Li M
中科院分区：
文献类型：
--
作者：
Su X;Ma J;Pan X;Zhao X;Chang W;Liu Z;Zhang X;Li M
在光合作用过程中，光系统I和II（PSI和PSII）对光驱动的电子传递是必不可少的。PSI中的激发能量转移发生得非常快，使其成为一种高效的能量转换器。在莱茵衣藻（Cr）中，捕光复合物I（LHCI）的多个单元与PSI核心结合并作为外周触角起作用，形成PSI-LHCI超复合物。与植物PSI-LHCI相比，CrPSI-LHCI显示出显著更大的触角，同时保持从LHCI到PSI的高效能量转移。在这里，我们报告的CrPSI-LHCI的结构，解决了冷冻电子显微镜，揭示了多达10个LHCI与PSI核心。这些结构提供了有关超复合物内天线组织和色素排列的详细信息。在触角中的高度填充和密切相关的叶绿素解释了在CrPSI-LHCI中的光捕获和激发能量转移的高效率。
During oxygenic photosynthesis, photosystems I and II (PSI and PSII) are essential for light-driven electron transport. Excitation energy transfer in PSI occurs extremely quickly, making it an efficient energy converter. In the algaChlamydomonas reinhardtii(Cr), multiple units of light-harvesting complex I (LHCI) bind to the PSI core and function as peripheral antennae, forming a PSI–LHCI supercomplex. CrPSI–LHCI shows significantly larger antennae compared with plant PSI–LHCI while maintaining highly efficient energy transfer from LHCI to PSI. Here, we report structures of CrPSI–LHCI, solved by cryo-electron microscopy, revealing that up to ten LHCIs are associated with the PSI core. The structures provide detailed information about antenna organization and pigment arrangement within the supercomplexes. Highly populated and closely associated chlorophylls in the antennae explain the high efficiency of light harvesting and excitation energy transfer in CrPSI–LHCI.