Research Group Nucleic Acid Chemistry, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen 37077, Germany.
Bioorg Med Chem. 2013 Oct 15;21(20):6171-80. doi: 10.1016/j.bmc.2013.04.007. Epub 2013 Apr 15.
Chemically stable nitroxide radicals that can be monitored by electron paramagnetic resonance (EPR) spectroscopy can provide information on structural and dynamic properties of functional RNA such as riboswitches. The convertible nucleoside approach is used to install 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) and 2,2,5,5-tetramethylpyrrolidin-1-oxyl (proxyl) labels at the exocyclic N(4)-amino group of cytidine and 2'-O-methylcytidine nucleotides in RNA. To obtain site-specifically labeled long riboswitch RNAs beyond the limit of solid-phase synthesis, we report the ligation of spin-labeled RNA using an in vitro selected deoxyribozyme as catalyst, and demonstrate the synthesis of TEMPO-labeled 53 nt SAM-III and 118 nt SAM-I riboswitch domains (SAM=S-adenosylmethionine).
能够通过电子顺磁共振（EPR）光谱监测的化学稳定的氮氧自由基可以提供有关功能性 RNA（如核酶）的结构和动态特性的信息。可转换核苷方法用于在胞苷和 2'-O-甲基胞苷核苷酸的环外 N(4)-氨基基团处安装 2,2,6,6-四甲基哌啶-1-氧自由基（TEMPO）和 2,2,5,5-四甲基吡咯烷-1-氧自由基（PROXYL）标记物。为了在固相合成的限制之外获得特异性标记的长核酶 RNA，我们报告了使用体外选择的脱氧核酶作为催化剂连接自旋标记的 RNA，并证明了 TEMPO 标记的 53 nt SAM-III 和 118 nt SAM-I 核酶结构域（SAM=S-腺苷甲硫氨酸）的合成。
