STRUCTURE DETERMINATION OF AN INTACT BACTERIAL SELF-SPLICING INTRON

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 有几类自然产生的催化RNA或核酶。了解这类生物催化剂如何促进其反应的重要性随着最近对50s核糖体结构的确定而变得明显，这表明所有活着的生物体中的蛋白质合成都发生在活性的rna中。 地点。核酶是最有可能是现代生物催化剂前体的分子，了解它们是如何促进反应的有助于深入了解酶的功能。本项目重点研究第一类催化RNA--I族自剪接内含子的结构。结构信息是理解和解释这类生物催化剂的生物学功能所必需的。 我们正朝着三个目标努力。 1.本项目的主要目的是确定完整的细菌I组自剪接内含子的高分辨X射线晶体结构。如果实现这一目标，将开展另外两个项目： 2.重金属离子和替代内含子抑制剂将被用来从结构上研究金属离子对I类内含子折叠和催化的作用。 3.通过对过渡态几何构型的稳定模拟，从结构上探讨了磷转移反应的过渡态。 这些研究将为20多年的生物化学提供结构基础。它还将提供对RNA催化的性质的化学见解，特别是对于尚未进行结构分析的RNA金属酶的例子。RNA催化是一个特别令人感兴趣的问题，因为RNA在几个自然过程中的作用至关重要，包括多肽键的形成和前mRNA的剪接。这些坐标将提供给科学界进行分析和实验设计。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. There are several classes of naturally occurring catalytic RNAs or ribozymes. The importance of understanding how this class of biocatalysts promotes their reactions became evident with the recent structure determination of the 50S ribosome, which demonstrated that protein synthesis in all living organisms occurs within an RNA active site. Ribozymes are the molecules most likely to be the progenitors of modern biological catalysts and understanding how they promote their reactions provides critical insight into enzymological function. This project focuses on the structure of the group I self-splicing intron, the first class of catalytic RNAs discovered. Structural information is necessary to understand and interpret the biological function of this class of biocatalyst. We are working toward three goals. 1. The primary aim of this project is to determine the high resolution x-ray crystal structure of an intact bacterial group I self-splicing intron. If this aim is achieved, two additional projects will be undertaken: 2. Heavy metal ions and alternative intron inhibitors will be used to structurally investigate how metal ions contribute to group I intron folding and catalysis. 3. The transition state of the phosphotransfer reaction will be structurally explored using stable mimics of the transition state geometry. These studies will provide a structural basis for more than 20 years of biochemistry. It will also provide chemical insights into the nature of RNA catalysis, particularly for an RNA metalloenzyme, an example of which has not yet been structurally analyzed. RNA catalysis is an issue of particular interest given the critical of role of RNA in several natural processes including peptide bond formation and pre-mRNA splicing. The coordinates will be made available to the scientific community for analysis and experimental design.