绿硫细菌光反应核心复合体的构造及能量传递机制研究

绿硫细菌是一类严格厌氧的光合细菌，其光反应系统包括外周天线绿小体、内周捕光天线FMO和反应中心(GsbRC)。在生理条件下，每个反应中心结合两个FMO形成绿硫细菌光反应核心复合体(2FMO-GsbRC)。尽管反应中心的结构此前已有报道，但其外周亚基结构不完整，完整光反应核心复合体的构造尚未见报道，且FMO与反应中心之间的能量传递机制尚不明确。本项目以嗜热型绿硫细菌为研究材料，采用机械破碎、差速离心、化学交联和凝胶层析等方法对绿硫细菌完整光反应核心复合体进行分离纯化；运用质谱和高效液相层析技术对复合体进行定性分析；利用单颗粒冷冻电镜技术解析复合体近原子分辨率的空间结构，并基于三维结构模型，明确复合体蛋白亚基间的相互作用，阐明复合体内部的电子传递和能量传递机制。

Green sulfur bacteria (GSB) are strictly anaerobic photosynthetic bacteria. The light reaction system of GSB comprises peripheral antenna chlorosome, energy-transferring protein FMO and reaction center (GsbRC). In vivo, each GsbRC binds two FMO, forming the light-reaction core complex (2FMO-GsbRC) of GSB. Though the structure of GsbRC had been resolved, the full-length structures of peripheral subunits remain incomplete, and the structure of the intact light reaction core complex is unknown, and the energy transfer mechanism between FMO and GsbRC is unclear. This project chooses the thermophilic GSB as research material, by jointly using the methods of disruption, centrifugation, chemical crosslinking and gel filtration to purify the intact light reaction core complex (2FMO-GsbRC) of GSB, and by using mass spectrum (MS)- high performance liquid chromatography (HPLC) to analyze the sample, and further utilizes the cryo-EM technique to resolve the atomic structure of this complex, aiming to clarify the protein-protein interactions and the possible energy transfer mechanism within the complex.