Institut Curie, Research Division, CNRS UMR 168, Paris 75248, France.
J Am Chem Soc. 2009 Dec 2;131(47):17270-6. doi: 10.1021/ja906076e.
Natural RNAs, unlike many proteins, have never been reported to form extended nanostructures, despite their wide variety of cellular functions. This is all the more striking, as synthetic DNA and RNA forming large nanostructures have long been successfully designed. Here, we show that DsrA, a 87-nt noncoding RNA of Escherichia coli, self-assembles into a hierarchy of nanostructures through antisense interactions of three contiguous self-complementary regions. Yet, the extended nanostructures, observed using atomic force microscopy (AFM) and fluorescence microscopy, are easily disrupted into >100 nm long helical bundles of DsrA filaments, including hundreds of DsrA monomers, and are surprisingly resistant to heat and urea denaturation. Molecular modeling demonstrates that this structural switch of DsrA nanostructures into filament bundles results from the relaxation of stored torsional constraints and suggests possible implications for DsrA regulatory function.
天然 RNA 与许多蛋白质不同，尽管它们具有广泛的细胞功能，但从未有报道称其形成延伸的纳米结构。这更加引人注目，因为合成 DNA 和 RNA 形成大型纳米结构早已成功设计。在这里，我们展示了大肠杆菌的 87nt 非编码 RNA DsrA 通过三个连续的自我互补区域的反义相互作用自组装成纳米结构层次。然而，使用原子力显微镜（AFM）和荧光显微镜观察到的延伸纳米结构很容易被破坏成 >100nm 长的 DsrA 纤维螺旋束，其中包括数百个 DsrA 单体，并且对热和脲变性具有惊人的抵抗力。分子建模表明，这种 DsrA 纳米结构向纤维束的结构转换是由于存储的扭转约束的松弛，并暗示了对 DsrA 调节功能的可能影响。
