Life Sciences Institute, Zhejiang University, 310058, Hangzhou, Zhejiang, China.
Institute of Organic Chemistry, Center for Molecular Biosciences Innsbruck, Leopold Franzens University, Innsbruck, A6020, Austria.
Nat Commun. 2019 Dec 16;10(1):5728. doi: 10.1038/s41467-019-13600-9.
Riboswitches are metabolite-sensing, conserved domains located in non-coding regions of mRNA that are central to regulation of gene expression. Here we report the first three-dimensional structure of the recently discovered S-adenosyl-L-methionine responsive SAM-VI riboswitch. SAM-VI adopts a unique fold and ligand pocket that are distinct from all other known SAM riboswitch classes. The ligand binds to the junctional region with its adenine tightly intercalated and Hoogsteen base-paired. Furthermore, we reveal the ligand discrimination mode of SAM-VI by additional X-ray structures of this riboswitch bound to S-adenosyl-L-homocysteine and a synthetic ligand mimic, in combination with isothermal titration calorimetry and fluorescence spectroscopy to explore binding thermodynamics and kinetics. The structure is further evaluated by analysis of ligand binding to SAM-VI mutants. It thus provides a thorough basis for developing synthetic SAM cofactors for applications in chemical and synthetic RNA biology.
Riboswitches 是代谢物感应的保守结构域，位于 mRNA 的非编码区域，是基因表达调控的核心。在这里，我们报告了最近发现的 S-腺苷-L-甲硫氨酸响应 SAM-VI 核糖开关的第一个三维结构。SAM-VI 采用了独特的折叠和配体口袋，与所有其他已知的 SAM 核糖开关类别明显不同。配体与连接区域结合，其腺嘌呤紧密嵌入并与 Hoogsteen 碱基配对。此外，我们通过结合等温滴定量热法和荧光光谱法，对该核糖开关与 S-腺苷-L-同型半胱氨酸和合成配体类似物结合的另外两个 X 射线结构，揭示了 SAM-VI 的配体识别模式，以探索结合热力学和动力学。通过对 SAM-VI 突变体与配体结合的分析进一步评估了该结构。因此，它为开发用于化学和合成 RNA 生物学的合成 SAM 辅因子提供了全面的基础。
Zotero 插件
