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

该子项目是利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 中心，不一定是研究者的机构。 在过去的十年中，前沿生物学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三维结构的了解是有限的。 RNA很难结晶;具有正常功能大小的RNA对于使用当前溶液NMR方法的结构测定来说太大。 最近，我们开发了一种新的方法，使用NMR光谱，同步加速器为基础的小角X射线散射（SAXS）和一种新的计算程序来解决大RNA在溶液中的结构。 通常，折叠良好的RNA结构由许多A型双链体填充。 如果已知这些双链体的相对方向和位置，则可以确定RNA的整体结构。 我们利用偶极耦合结构周期性相关性推导了双链体的相对取向，并利用小角X射线散射数据抑制了双链体的相对位置。 我们已经使用腺嘌呤-核糖A开关RNA（71 nt）证明了这种方法。 一份描述该方法的手稿目前正在由美国国家科学院院刊审查。 此外，我们已经应用该方法来解决的全球结构的102-nt的RNA片段，起到了作用，作为一个翻译增强子在芜菁皱纹病毒（tcv）的RNA和手稿，后者目前正在准备中。 我们的研究是由美国国立卫生研究院内部研究补助金YXW* 资助。 APS的同步加速器光束线使这种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.