蛋白翻译因子EF-G催化tRNA2-mRNA移位过程中核糖体构象变化的研究

The functions of the ribosome can be separated into four phases, including initiation, elongation, termination of protein synthesis, and the recycling phase, each of which is governed by specific protein factors. Elongation factor G (EF-G) translocates the tRNAs from A P sites to P E sites. Biochemical and crystallographic studies of EF-G and ribosome complex have offered exciting insights into the translocation mechanisms. However, translocation is the least understood step of the elongation cycle since it involves large-scale movements of tRNAs, mRNA, the ribosome, and EF-G. In this application, we plan to combine genetic and biochemical methods, foot-printing, FRET and structural analysis to understand the mechanism of tRNA2-mRNA translocation, which may help us to understand the antibiotic action principle and design the novel antibiotics.

核糖体蛋白翻译的过程包括起始、延伸、终止和再循环，每一个步骤都由特定的蛋白因子参与并调控，其中，翻译延长因子EF-G参与延长循环，它催化A、P位点的2个tRNA移位至P、E位点。虽然近年有关EF-G与核糖体复合物的结构生物学研究已经取得了很多进展，但是其催化tRNA2-mRNA移位的具体机制尚不清楚。本项目以EF-G和核糖体为研究对象，首先根据已有的核糖体结构信息设计EF-G突变位点，用生化实验鉴定其功能，然后运用结构解析、Foot-printing和FRET等方法，研究EF-G催化tRNA2-mRNA移位过程中核糖体的构象变化。综合分析上述实验结果，阐明EF-G对tRNA移位的调控机制，同时为新型抗生素的设计提供研究思路。