NMR SOLUTION STRUCTURES OF RNA

RNA可以催化化学反应的发现导致了 核糖核酸的许多新的生物学和生化作用的鉴定 细胞。然而，尽管付出了巨大的努力，但目前几乎没有什么 关于RNA的三维结构的信息。这种情况 与蛋白质形成鲜明对比的是，在蛋白质中，数百个 生物活性酶是已知的，这些数据是常规使用的 以帮助解开这些分子的分子作用机制。 在这项提议中，最先进的异核多维核磁共振 光谱学将被用来探测一个 各种具有重要生物学意义的RNA和RNA结构基序。零件 这一项目的开发和优化涉及到异核 用于共振归属和结构的2D、3D和4D核磁共振技术 RNA的测定。类似的技术已经彻底改变了 蛋白质的溶液结构测定，但尚未确定 用于核酸的。生物信息学方法学的最新进展 产生毫克量的13C和/或15N标记的RNA，将 现在使执行更详细的结构确定成为可能 更大的RNA。该项目的一个目标侧重于识别和 RNA折叠基序的结构测定。以下系统 会研究：一)RNA发夹属于多发的 GNRA(其中N是任何核苷酸，R是A或G)和CUUG四环 家族；ii)RNA三联体；以及iii)天然存在的RNA双链 包含内部环或“不匹配”的碱基对。这些研究 将为我们提供大量关于RNA构建块的新信息 三级结构。研究RNA结构基序的重要性 在生物学功能中，由一个片段组成的蛋白质-RNA复合体 所含的信号识别粒子(SRP)RNA及其 位点特异性结合蛋白，SRP-19蛋白，将通过 核磁共振。该RNA结合位点含有GNRR四环，该系统 将被用来确定19kD蛋白的结合如何影响 RNA发夹的结构。这些结果将导致更好的 理解RNA结构基序在蛋白质-RNA中的作用 承认。

The discovery that RNA can catalyze chemical reactions has led to the identification of many new biological and biochemical roles for RNAs in cells. However despite significant effort, there is presently little information on the three-dimensional structures of RNA. This situation is in contrast to proteins where X-ray or NMR structures of hundreds of biologically active enzymes are known and these data are routinely used to help unravel the molecular mechanisms of action of these molecules. In this proposal state-of-the-art heteronuclear multi-dimensional NMR spectroscopy will be used to probe the structure and dynamics of a variety of biologically important RNAs and RNA structural motifs. Part of this project entails development and optimization of heteronuclear 2D, 3D and 4D NMR techniques for resonance assignment and structure determinations of RNAs. Similar techniques have revolutionized the solution structure determinations of proteins but they have yet to be applied to nucleic acids. Recent advances in the methodology for generating milligram quantities of 13C and/or 15N labelled RNAs, will now make it possible to perform more detailed structure determination of larger RNAs. One goal of this project focuses on identification and structure determination of RNA folding motifs. The following systems will be studied: i) RNA hairpins belonging to the frequently occurring GNRA (where N is any nucleotide and R is A or G) and CUUG tetraloop families; ii) RNA triplexes; and iii) naturally occurring RNA duplexes that contain internal loops or 'mismatched' base pairs. The studies will give us a wealth of new information on the building blocks of RNA tertiary structure. To investigate importance of RNA structural motifs in biological functions a protein-RNA complex consisting of a fragment of the signal recognition particle (SRP) RNA containing and its site-specific binding protein, the SRP-19 protein, will be studied by NMR. This RNA binding site contains a GNRR tetraloop and this system will be used to determine how the binding of this 19kD protein affects the structure of the RNA hairpin. These result will lead to a better understanding of the role of RNA structural motifs in protein-RNA recognition.