COMBINED SAXS & NMR TO STUDY THE STRUCTURE & DYNAMICS OF LARGE RNA MOLECULES

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。 在过去的十年里，前沿生物学领域最大的进步之一是发现了非编码RNA在生物过程中扮演的各种角色。然而，由于各种原因，我们对RNA的三维结构的了解是有限的。RNA很难结晶；正常功能大小的RNA太大，无法用目前的溶液核磁共振方法确定结构。最近，我们发展了一种新的方法，利用核磁共振光谱、基于同步加速器的小角X射线散射(SAXS)和一种新的计算程序来求解溶液中大RNA的结构。一般来说，一个折叠良好的RNA结构中充满了许多A型双链。如果已知这些双链的相对取向和位置，就可以确定RNA的全局结构。我们利用剩余偶极耦合-结构周期关联得到了双链的相对取向，并利用SAXS数据抑制了双链的相对位置。我们已经用腺嘌呤-核糖体A开关RNA(71nt)证明了这一方法。描述这一方法的手稿目前正在接受《美国国家科学院院刊》的审查。此外，我们还应用该方法解决了在芜菁皱缩病毒(TCV)RNA中起翻译增强子作用的102-NT RNA片段的全局结构，后者的手稿目前正在准备中。我们的研究是由国立卫生研究院对YXW*的内部研究拨款资助的。APS对同步加速器光束线的访问使这一新方法的开发成为可能。

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. One of the greatest advances in frontier biology in the past decade is the discovery of a vast variety of roles non-coding RNA played in biological processes. However, our knowledge about the three-dimensional structures of RNA is limited for various reasons. RNAs are difficult to crystallize; RNAs with normal functional sizes are too large for structure determination using the current solution NMR methods. Recently, we have developed a novel method that uses NMR spectroscopy, synchrotron-based small angle X-ray scattering (SAXS) and a novel computational program to solve structures of large RNAs in solution. In general, a well-folded RNA structure is packed with a number of A-form duplexes. The global structure of RNAs can be determined if the relative orientation and position of those duplexes are known. We derive the relative orientation of duplexes using residual dipolar coupling-structure periodicity correlation and restrain the relative positions of duplexes using SAXS data. We have demonstrated this method using adenine-riboA switch RNA (71nt). A manuscript that describes the methodology is currently under review by Proceedings of the National Academy of Science. Furthermore, we have applied the method to solve the global structure of a 102-nt RNA fragment that plays a role as a translational enhancer in turnip crinkle virus (tcv) RNA and a manuscript for the latter is currently in preparation. Our research is funded by an NIH intramural research grant to YXW*. The access to the synchrotron beamline at APS has made this new methodology development possible.