Structure of phycobilisome from the red alga Griffithsia pacifica
Structure of phycobilisome from the red alga Griffithsia pacifica
复制标题
红藻 Griffithsia pacifica 藻胆体的结构
DOI：
10.1038/nature24278
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发表时间：
2017-11-02
期刊：
影响因子：
64.8
通讯作者：
Sui, Sen-Fang
中科院分区：
文献类型：
--
作者：
Zhang, Jun;Ma, Jianfei;Sui, Sen-Fang
地球上的生命依靠光合作用将太阳能转化为化学能。光合作用的有机体已经开发出各种捕光系统来捕捉阳光。最大的捕光复合体是藻胆体(PBS)，它是蓝藻和红藻的主要捕光天线。它由藻胆蛋白和连接蛋白组成，但PBS的组装机制和能量传递途径尚不清楚。在这里，我们报道了用单粒子冷冻电子显微镜从红藻中获得的重达16.8百万吨、分辨率为3.5 的PbS的结构。我们模拟了862个蛋白质亚基，包括4个核心连接体，16个杆状核心连接体和52个杆状连接体，总共定位了2,048个发色团。这种结构揭示了连接体和藻胆蛋白之间特定相互作用的机制，以及连接体骨架的形成。这些结果为我们理解复杂的组装和PBS内的能量转移机制提供了坚实的结构基础。
Life on Earth depends on photosynthesis for its conversion of solar energy to chemical energy. Photosynthetic organisms have developed a variety of light-harvesting systems to capture sunlight. The largest light-harvesting complex is the phycobilisome (PBS), the main light-harvesting antenna in cyanobacteria and red algae. It is composed of phycobiliproteins and linker proteins but the assembly mechanisms and energy transfer pathways of the PBS are not well understood. Here we report the structure of a 16.8-megadalton PBS from a red alga at 3.5 Å resolution obtained by single-particle cryo-electron microscopy. We modelled 862 protein subunits, including 4 linkers in the core, 16 rod–core linkers and 52 rod linkers, and located a total of 2,048 chromophores. This structure reveals the mechanisms underlying specific interactions between linkers and phycobiliproteins, and the formation of linker skeletons. These results provide a firm structural basis for our understanding of complex assembly and the mechanisms of energy transfer within the PBS.