植物中包括叶绿素在内的卟啉合成的共同前体是5-氨基乙酰丙酸。谷氨酰-tRNA还原酶是合成5-氨基乙酰丙酸的关键限速酶，也是植物调控5-氨基乙酰丙酸和叶绿素合成的一个重要靶位点。高等植物中特有的FLU蛋白是能够与谷氨酰-tRNA还原酶相互作用的负调控因子，但其负调控的分子机理一直不清楚。本项目拟在申请人证明GluBP对谷氨酰-tRNA还原酶的正调控作用并通过解析GluBP与谷氨酰-tRNA还原酶蛋白复合体的晶体结构来阐明其正调控分子机理的基础上，通过获取谷氨酰-tRNA还原酶、GluBP及FLU三元复合物晶体并分析该晶体结构的方式揭示三者间的相互作用关系，同时结合体内外生理生化实验数据来解释FLU蛋白负调控叶绿素合成的分子机理和结构基础。本研究对于人们进一步了解叶绿素合成及光合作用的调控有重要意义。

In plant, 5-aminoleculinic acid is a universal precursor for all tetrapyrrole compounds including chlorophyll. Glu-tRNA reductase is a rate limiting enzyme and a hub of regulation target in 5-aminoleculinic acid synthesis. In higher plant, FLU protein can interact with Glu-tRNA reductase, and is a negative regulator of the enzyme. The molecular mechanism of FLU protein’s negative regulation role is unclear. We have confirmed that GluBP is a positive regulator of Glu-tRNA reductase, and explained the molecular mechanism through analyzing the crystal structure of protein complex of GluBP and Glu-tRNA reductase. Based on the previous work, we want to get the crystal structure of the triple protein complex of GluBP, FLU and Glu-tRNA reductase, and unveil the interaction relationship between the proteins through analyzing the crystal structure. Combined with in vivo and in vitro physiological and biochemical data, the molecular mechanism and structural basis of FLU protein’s negative regulation function in chlorophyll synthesis can be explained. This research is important for people to understand the regulation of the chlorophyll synthesis and photosynthesis.