Viruses require multifunctional structured RNAs to hijack their host’s biochemistry, but their mechanisms can be obscured by the difficulty of solving conformationally dynamic RNA structures. Using cryo–electron microscopy (cryo-EM), we visualized the structure of the mysterious viral transfer RNA (tRNA)–like structure (TLS) from the brome mosaic virus, which affects replication, translation, and genome encapsidation. Structures in isolation and those bound to tyrosyl-tRNA synthetase (TyrRS) show that this ~55-kilodalton purported tRNA mimic undergoes large conformational rearrangements to bind TyrRS in a form that differs substantially from that of tRNA. Our study reveals how viral RNAs can use a combination of static and dynamic RNA structures to bind host machinery through highly noncanonical interactions, and we highlight the utility of cryo-EM for visualizing small, conformationally dynamic structured RNAs.

中文翻译：

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病毒 RNA 利用 tRNA 样结构的动态构象变化劫持宿主机器

病毒需要多功能的结构化 RNA 来劫持宿主的生物化学，但​​它们的机制可能会因难以解决构象动态 RNA 结构而变得模糊不清。使用低温电子显微镜 (cryo-EM)，我们可视化了来自雀麦花叶病毒的神秘病毒转移 RNA (tRNA) 样结构 (TLS) 的结构，它影响复制、翻译和基因组封装。分离的结构和与酪氨酰-tRNA 合成酶 (TyrRS) 结合的结构表明，这种据称为 55 千道尔顿的 tRNA 模拟物经历了大的构象重排，以与 tRNA 大不相同的形式结合 TyrRS。我们的研究揭示了病毒 RNA 如何使用静态和动态 RNA 结构的组合通过高度非典型的相互作用结合宿主机器，