利用冷冻电镜（cryo-EM），研究人员可视化了来自雀麦花叶病毒的病毒转运RNA（tRNA）样结构（TLS）的结构，它影响复制、翻译和基因组封装。孤立的结构和与酪氨酰-tRNA合成酶（TyrRS）结合的结构显示，这个大约55千兆的tRNA模拟物经历了巨大的构象重排，以一种与tRNA大不相同的形式跟TyrRS结合。
这项研究揭示了病毒RNA如何利用静态和动态RNA结构的组合通过高度非经典的相互作用与宿主机器结合，并且研究人员强调了冷冻电镜在可视化小型、构象动态结构RNA方面的实用性。
据了解，病毒需要多功能的结构化RNA来劫持其宿主的生物化学，但由于难以解决构象动态的RNA结构，其机制可能被掩盖。
附：英文原文
Title: A viral RNA hijacks host machinery using dynamic conformational changes of a tRNA-like structure
Author: Steve L. Bonilla, Madeline E. Sherlock, Andrea MacFadden, Jeffrey S. Kieft
Issue&Volume: 2021-11-19
Abstract: 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.
DOI: abe8526
Source: https://www.science.org/doi/10.1126/science.abe8526