Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.
University of Chinese Academy of Sciences, Beijing, China.
Nature. 2023 Jan;613(7945):783-789. doi: 10.1038/s41586-022-05604-1. Epub 2023 Jan 11.
Efficient and accurate termination is required for gene transcription in all living organisms. Cellular RNA polymerases in both bacteria and eukaryotes can terminate their transcription through a factor-independent termination pathway-called intrinsic termination transcription in bacteria-in which RNA polymerase recognizes terminator sequences, stops nucleotide addition and releases nascent RNA spontaneously. Here we report a set of single-particle cryo-electron microscopy structures of Escherichia coli transcription intrinsic termination complexes representing key intermediate states of the event. The structures show how RNA polymerase pauses at terminator sequences, how the terminator RNA hairpin folds inside RNA polymerase, and how RNA polymerase rewinds the transcription bubble to release RNA and then DNA. These macromolecular snapshots define a structural mechanism for bacterial intrinsic termination and a pathway for RNA release and DNA collapse that is relevant for factor-independent termination by all RNA polymerases.
所有生物的基因转录都需要高效且准确的终止。细菌和真核生物中的细胞 RNA 聚合酶都可以通过一种无需因子的终止途径终止转录，这种途径在细菌中被称为内在终止转录，其中 RNA 聚合酶识别终止序列，停止核苷酸的添加并自发释放新生 RNA。在这里，我们报告了一组大肠杆菌转录内在终止复合物的单颗粒冷冻电子显微镜结构，这些结构代表了该事件的关键中间状态。这些结构显示了 RNA 聚合酶如何在终止序列处暂停，终止 RNA 发夹如何在 RNA 聚合酶内部折叠，以及 RNA 聚合酶如何反转转录泡以释放 RNA 然后是 DNA。这些大分子快照定义了细菌内在终止的结构机制，以及 RNA 释放和 DNA 崩溃的途径，这对于所有 RNA 聚合酶的无因子终止都是相关的。
