Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, Innsbruck 6020, Austria.
Architecture et Réactivité de l'ARN - CNRS UPR 9002, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire, 2 Allée Conrad Roentgen, Strasbourg 67084, France.
J Am Chem Soc. 2022 Jun 15;144(23):10344-10352. doi: 10.1021/jacs.2c01877. Epub 2022 Jun 6.
Atomic mutagenesis is the key to advance our understanding of RNA recognition and RNA catalysis. To this end, deazanucleosides are utilized to evaluate the participation of specific atoms in these processes. One of the remaining challenges is access to RNA-containing 1-deazaguanosine (cG). Here, we present the synthesis of this nucleoside and its phosphoramidite, allowing first time access to cG-modified RNA. Thermodynamic analyses revealed the base pairing parameters for cG-modified RNA. Furthermore, by NMR spectroscopy, a cG-triggered switch of Watson-Crick into Hoogsteen pairing in HIV-2 TAR RNA was identified. Additionally, using X-ray structure analysis, a guanine-phosphate backbone interaction affecting RNA fold stability was characterized, and finally, the critical impact of an active-site guanine in twister ribozyme on the phosphodiester cleavage was revealed. Taken together, our study lays the synthetic basis for cG-modified RNA and demonstrates the power of the completed deazanucleoside toolbox for RNA atomic mutagenesis needed to achieve in-depth understanding of RNA recognition and catalysis.
原子诱变是深入了解 RNA 识别和 RNA 催化的关键。为此，我们利用去氮核苷来评估特定原子在这些过程中的参与程度。目前仍面临的挑战之一是获得含有 1-去氮鸟苷（cG）的 RNA。在这里，我们介绍了该核苷及其亚磷酰胺的合成方法，首次获得了 cG 修饰的 RNA。热力学分析揭示了 cG 修饰 RNA 的碱基配对参数。此外，通过 NMR 光谱学，我们在 HIV-2 TAR RNA 中发现了 cG 触发的 Watson-Crick 向 Hoogsteen 配对的转变。此外，通过 X 射线结构分析，我们还研究了影响 RNA 折叠稳定性的鸟嘌呤-磷酸骨架相互作用，并最终揭示了在扭曲酶核酶中活性位点鸟嘌呤对磷酸二酯键切割的关键影响。综上所述，我们的研究为 cG 修饰的 RNA 奠定了合成基础，并展示了完整的去氮核苷工具包在 RNA 原子诱变方面的强大功能，这对于深入了解 RNA 识别和催化是必需的。
