STRUCTURE AND CATALYSIS OF AN RNA ENZYME

描述：这里提出的研究的全球目标是 了解一个基本的问题，一个小的RNA酶，称为 锤头状核酶，有效。 使用传统的和 时间分辨X射线晶体学实验，以及合成 修饰的RNA，最近阐明的基态 锤头状核酶的结构是催化相关的， 测试. 在这样做的时候，理解催化剂之间的关系， 通过研究RNA的结构， 锤头状核酶在沿着RNA的各个重要点上的位置 裂解反应坐标 中所述方案的具体目标 本研究的建议是：（1）捕捉晶体结构的 锤头状RNA切割中间体;（2）获得晶体结构 （3）在切割后捕获锤头状RNA的结构; 切割的锤头状核酶连接过程中的限速物质 底物;（4）获得锤头状RNA切割反应的结构 过渡态类似物;（5）理解的结构基础 增强催化的锤头状RNA修饰;和（6）选择 一种结合并锁定锤头状RNA的蛋白质， 活性构象，并确定其晶体结构 RNA-蛋白质复合物。 这六个具体目标都是为了探索， 独立地，这种小RNA酶的切割机制。 锤头状核酶作为靶向治疗剂的潜在用途 RNA病毒（如HIV）和病理性mRNA（如癌基因 转录本）目前是医学研究的一个活跃领域， 社区 锤头状核酶作为潜在的药物， 特别感兴趣，因为它们可以证明用于治疗条件 否则就很难解决 其中一个主要的动机， 这里提出的研究，除了回答一个基本的问题， 科学性，是为科学和 医学界，使更有效的核糖体为基础的药物， 被设计。

DESCRIPTION: The global objective of the research proposed here is to understand the fundamental question of how a small RNA enzyme, called the hammerhead ribozyme, works. Using a combination of conventional and time-resolved X-ray crystallography experiments, together with synthetically modified RNA, the hypothesis that the recently elucidated ground-state structure of the hammerhead ribozyme is catalytically relevant will be tested. In doing so, an understanding of the relationship between catalytic RNA structure and function will be obtained by investigating the structures of the hammerhead ribozyme at various important points along the RNA cleavage reaction coordinate. The specific aims of the program described in this research proposal are: (1) to capture the crystal structures of hammerhead RNA cleavage intermediates; (2) to obtain the crystal structure of the hammerhead RNA after cleavage; (3) to capture structures of rate-limiting species during ligation of the cleaved hammerhead ribozyme substrate; (4) to obtain the structure of a hammerhead RNA cleavage reaction transition-state analog; (5) to understand the structural basis of catalysis-enhancing hammerhead RNA modifications; and (6) to select for a protein that binds to, and locks, the hammerhead RNA in a catalytically active conformation, and to determine the crystal structure of this RNA-protein complex. These six specific aims are each designed to probe, independently, the cleavage mechanism of this small RNA enzyme. The potential use of hammerhead ribozymes as therapeutic agents that target RNA viruses (such as HIV) and pathological mRNAs (such as oncogene transcripts) is currently an active area of research in the medical community. Hammerhead ribozymes as potential pharmaceuticals are of particular interest because they may prove usful for treating conditions that have proven otherwise intractable. One of the primary motives for the research proposed here, in addition to answering questions of a basic scientific nature, is to provide practical information to the scientific and medical communities to enable more potent ribosome-based pharmaceuticals to be designed.