CAREER: Structure, Dynamics, and Function of the Packaging RNA Studied using Site-directed Spin Labeling

核酸在生物过程中是必不可少的，有关核酸结构和构象变化的信息对于理解其功能至关重要。本项目将建立一种研究核酸构象的新方法。该方法基于位点定向自旋标记（SDSL）技术，其中结构和动态信息来源于附着在大分子特定位点的稳定氮氧化物自由基。该研究将探索一种氮氧化物探针，它可以以一种高效和经济的方式附着在任意核酸序列上。一对氮氧化物之间的纳米级距离将被测量，得到的数据将被用于绘制核酸的整体结构。为了证明SDSL方法，将研究没有先前已知高分辨率结构的核酸分子的全局结构。其中包括包装RNA，它在当今已知的最强生物分子马达中起着至关重要的作用：phi29 DNA包装马达。该研究将为在没有事先高分辨率结构的情况下对核酸和核酸/蛋白复合物进行广泛的SDSL研究开创先例。更广泛的影响：PI将在本科和研究生阶段建立创新的跨学科项目，将研究和教学结合起来。将开设一门新的通识教育课程，名为“基因、生命和社会”。本课程将以严谨而精确的核酸结构和功能的分子描述来呈现基因的本质，并将科学概念与当代社会问题联系起来，如我们社会的进化和多样性。该课程将使用“BioSIGHT”多媒体教学平台，这是由美国国家科学基金会资助的南加州大学中心开发的。该课程将面向大量理科和非理科学生，并将通过公开讲座和网站推广给高中教师。

Nucleic acids are essential in biological processes, and information on nucleic acids structure and conformational changes is critical in understanding their functions. This project will establish a new method for investigating nucleic acids conformations. The method is based on the site-directed spin labeling (SDSL) technique, where structural and dynamic information is derived from a stable nitroxide radical attached at a specific site of a macro-molecule. The research will explore a nitroxide probe that can be attached, in an efficient and cost-effective manner, to arbitrary nucleic acid sequences. Nanometer distances between a pair of such nitroxides will be measured, and the resulting data will be utilized to map the global structures of nucleic acids. To demonstrate the SDSL methods, global structures of nucleic acid molecules without prior known high-resolution structures will be studied. These include the packaging RNA that plays an essential role in the strongest bio-molecular motor known today : the phi29 DNA packaging motor. The studies will set a precedent for a wide range of SDSL studies on nucleic acids and nucleic acid/protein complexes without prior high-resolution structures. Broader Impacts: The PI will establish innovative, inter-disciplinary programs that integrate research and teaching at both the undergraduate and graduate level. A new general education course, called "Genes, Life, and Society", will be developed. The course will present the nature of genes with rigorous and precise molecular descriptions of nucleic acids structure and function, and will link the scientific concepts with contemporary societal issues such as evolution and diversity of our society. The course will utilize "BioSIGHT", a multi-media teaching platform being developed at an NSF-funded center at USC. The class will target a large population of science and non-science students, and will be used in outreach programs to high-school teachers through public lectures and web sites.