State Key Laboratory of Elemento-Organic Chemistry and Department of Chemical Biology, College of Chemistry, Nankai University, Tianjin 300071, China.
Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, Ljubljana, Slovenia.
J Am Chem Soc. 2020 Mar 11;142(10):4739-4748. doi: 10.1021/jacs.9b13207. Epub 2020 Feb 26.
Fluorinated RNA molecules, particularly 2'-F RNA, have found a wide range of applications in RNA therapeutics, RNA aptamers, and ribozymes and as F NMR probes for elucidating RNA structure. Owing to the instability of 4'-F ribonucleosides, synthesis of 4'-F-modified RNA has long been a challenge. In this study, we developed a strategy for synthesizing a 4'-F-uridine (U) phosphoramidite, and we used it to prepare 4'-F RNA successfully. In the context of an RNA strand, U, which existed in a North conformation, was reasonably stable and resembled unmodified uridine well. The F NMR signal of U was sensitive to RNA secondary structure, with a chemical shift dispersion as large as 4 ppm (compared with <1 ppm for U), which makes it a valuable probe for discriminating single-stranded RNA and A-type, B-type, and mismatched duplexes. In addition, we demonstrated that because RNA-processing enzymes treated U the same as unmodified uridine, U could be used to monitor RNA structural dynamics and enzyme-mediated RNA processing. Taken together, our results indicate that 4'-F RNA represents a probe with wide utility for elucidation of RNA structure and function by means of F NMR spectroscopy.
氟代 RNA 分子，特别是 2'-F RNA，在 RNA 治疗学、RNA 适体和核酶领域以及作为 F NMR 探针用于阐明 RNA 结构方面有广泛的应用。由于 4'-F 核糖核苷的不稳定性，4'-F 修饰 RNA 的合成一直是一个挑战。在本研究中，我们开发了一种合成 4'-F-尿嘧啶（U）亚磷酰胺的策略，并成功地用它来制备 4'-F RNA。在 RNA 链的上下文中，处于 North 构象的 U 是合理稳定的，并且与未修饰的尿嘧啶非常相似。U 的 F NMR 信号对 RNA 二级结构敏感，化学位移分散度高达 4 ppm（相比之下，U 的化学位移分散度小于 1 ppm），这使其成为区分单链 RNA 和 A 型、B 型和错配双链的有价值的探针。此外，我们证明由于 RNA 加工酶将 U 与未修饰的尿嘧啶同等处理，因此 U 可用于监测 RNA 结构动力学和酶介导的 RNA 加工。总之，我们的结果表明 4'-F RNA 代表了一种探针，通过 F NMR 光谱学可以广泛用于阐明 RNA 结构和功能。
