Zielinski Kara A, Sui Shuo, Pabit Suzette A, Rivera Daniel A, Wang Tong, Hu Qingyue, Kashipathy Maithri M, Lisova Stella, Schaffer Chris B, Mariani Valerio, Hunter Mark S, Kupitz Christopher, Moss Frank R, Poitevin Frédéric P, Grant Thomas D, Pollack Lois
School of Applied and Engineering Physics, Cornell University; Ithaca NY 14853 USA.
Meinig School of Biomedical Engineering, Cornell University; Ithaca NY 14853 USA.
bioRxiv. 2023 May 24:2023.05.24.541763. doi: 10.1101/2023.05.24.541763.
RNA macromolecules, like proteins, fold to assume shapes that are intimately connected to their broadly recognized biological functions; however, because of their high charge and dynamic nature, RNA structures are far more challenging to determine. We introduce an approach that exploits the high brilliance of x-ray free electron laser sources to reveal the formation and ready identification of Å scale features in structured and unstructured RNAs. New structural signatures of RNA secondary and tertiary structures are identified through wide angle solution scattering experiments. With millisecond time resolution, we observe an RNA fold from a dynamically varying single strand through a base paired intermediate to assume a triple helix conformation. While the backbone orchestrates the folding, the final structure is locked in by base stacking. In addition to understanding how RNA triplexes form and thereby function as dynamic signaling elements, this new method can vastly increase the rate of structure determination for these biologically essential, but mostly uncharacterized macromolecules.
RNA大分子与蛋白质一样，会折叠成与它们被广泛认可的生物学功能密切相关的形状；然而，由于其高电荷和动态性质，RNA结构的确定要困难得多。我们介绍一种利用X射线自由电子激光源的高亮度来揭示结构化和非结构化RNA中埃尺度特征的形成及快速识别的方法。通过广角溶液散射实验确定了RNA二级和三级结构的新结构特征。以毫秒级的时间分辨率，我们观察到一条RNA从动态变化的单链通过碱基配对中间体折叠成三螺旋构象。虽然主链协调折叠过程，但最终结构通过碱基堆积固定下来。除了了解RNA三链体如何形成并作为动态信号元件发挥作用外，这种新方法还可以大幅提高这些对生物学至关重要但大多未被表征的大分子的结构确定速度。
