Crystal Structure of the Ribosome

项目描述（由申请人提供）：该项目的主要目的是：(1)获得完整的70S核糖体与mRNA和tRNA复合物的高分辨率晶体结构；(2)利用x射线晶体学解决核糖体的新功能复合物的结构。第一个目标将通过改进纯化、结晶和数据收集的参数，以及通过从不同生物体中提取核糖体的结晶来实现。完整核糖体的高分辨率结构将提供有关核糖体如何与mRNA和tRNA相互作用的分子基础，两个核糖体亚基如何相互作用以及分离核糖体亚基结构紊乱的分子特征的详细结构的新信息。我们计划求解70S核糖体与其不同功能配体结合的新功能复合物的结构，包括翻译延伸因子和终止因子。我们还计划研究与含有下游假结和二级结构元件的mrna结合的核糖体的结构。这些研究将有助于从核糖体动力学的角度在原子分辨率上理解蛋白质合成机制的最终目标。这一信息对于理解许多针对细菌核糖体的重要抗生素的作用机制也很重要，可能会导致设计出能够绕过许多病原体中进化出的耐药机制的新药。与含有假结和发夹的mRNA结合的核糖体的结构将为理解这些mRNA结构元件如何诱导逆转录病毒和其他RNA动物病毒中下游基因表达所必需的翻译移框事件提供结构基础。

DESCRIPTION (provided by applicant): The primary aims of this project are to (1) obtain a high-resolution crystal structure of the complete 70S ribosome in complex with mRNA and tRNA, and (2) solve the structures of new functional complexes of the ribosome, using X-ray crystallography. The first aim will be approached by improving parameters of purification, crystallization and data collection, and by crystallization of ribosomes from different organisms. A high-resolution structure of the complete ribosome will provide new information about the molecular basis of how the ribosome interacts with mRNA and tRNA, how the two ribosomal subunits interact with each other, and the detailed structures of molecular features that are disordered in structures of the isolated ribosomal subunits. We plan to solve the structures of new functional complexes of the 70S ribosome bound to its different functional ligands, including translational elongation factors and termination factors. We also plan to study the structures of ribosomes bound to mRNAs containing downstream pseudoknots and secondary structure elements. These studies will contribute toward the ultimate goal of understanding the mechanism of protein synthesis in terms of ribosomal dynamics at atomic resolution. This information will also be important in understanding the mechanisms of action of the many important antibiotics that target bacterial ribosomes, possibly leading to the design of novel drugs that are able to circumvent resistance mechanisms that have evolved in many pathogens. Structures of ribosomes bound to pseudoknot- and hairpin-containing mRNAs will provide a structural basis for understanding how these mRNA structural elements induce translational frameshifting events that are essential for expression of downstream genes in retroviruses and other RNA animal viruses.