Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California.
Wiley Interdiscip Rev RNA. 2020 Jul;11(4):e1589. doi: 10.1002/wrna.1589. Epub 2020 Feb 11.
Recent cryo-EM structures of a group II intron caught in the process of invading DNA have given new insight into the mechanisms of both splicing and retrotransposition. Conformational dynamics involving the branch-site helix domain VI are responsible for substrate exchange between the two steps of splicing. These structural rearrangements have strong parallels with the movement of the branch-site helix in the spliceosome during catalysis. This is strong evidence for the spliceosome evolving from a group II intron ancestor. We observe other topological changes in the overall structure of the catalytic domain V that may occur in the spliceosome as well. Therefore, studying group II introns not only provides us with insight into the evolutionary origins of the spliceosome, but also may inform the design of experiments to further probe structure-function relationships in this eukaryotic splicing apparatus. This article is categorized under: RNA Processing > Splicing Mechanisms RNA Structure and Dynamics > RNA Structure, Dynamics, and Chemistry RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems RNA Evolution and Genomics > RNA and Ribonucleoprotein Evolution.
最近捕获到的处于入侵 DNA 过程中的 II 组内含子的冷冻电镜结构，为剪接和 retrotransposition 的机制提供了新的见解。涉及分支位点螺旋域 VI 的构象动力学负责剪接两步之间的底物交换。这些结构重排与剪接体催化过程中分支位点螺旋的运动具有很强的相似性。这为剪接体是从 II 组内含子祖先进化而来提供了有力证据。我们还观察到催化结构域 V 的整体结构中可能发生的其他拓扑变化。因此，研究 II 组内含子不仅使我们深入了解剪接体的进化起源，而且还可能为设计实验提供信息，以进一步探索这个真核剪接装置中的结构-功能关系。本文属于以下类别：RNA 加工 > 剪接机制 RNA 结构和动态 > RNA 结构、动态和化学 RNA 结构和动态 > RNA 结构对生物系统的影响 RNA 进化和基因组学 > RNA 和核糖核蛋白进化。
