CEITEC-Central European Institute of Technology, Masaryk University, CZ-62500 Brno, Czech Republic.
CEITEC-Central European Institute of Technology, Masaryk University, CZ-62500 Brno, Czech Republic
Proc Natl Acad Sci U S A. 2017 Oct 17;114(42):11133-11138. doi: 10.1073/pnas.1712450114. Epub 2017 Oct 4.
RNA polymerase II contains a long C-terminal domain (CTD) that regulates interactions at the site of transcription. The CTD architecture remains poorly understood due to its low sequence complexity, dynamic phosphorylation patterns, and structural variability. We used integrative structural biology to visualize the architecture of the CTD in complex with Rtt103, a 3'-end RNA-processing and transcription termination factor. Rtt103 forms homodimers via its long coiled-coil domain and associates densely on the repetitive sequence of the phosphorylated CTD via its N-terminal CTD-interacting domain. The CTD-Rtt103 association opens the compact random coil structure of the CTD, leading to a beads-on-a-string topology in which the long rod-shaped Rtt103 dimers define the topological and mobility restraints of the entire assembly. These findings underpin the importance of the structural plasticity of the CTD, which is templated by a particular set of CTD-binding proteins.
RNA 聚合酶 II 含有一个长的 C 端结构域（CTD），它调节转录部位的相互作用。由于 CTD 结构具有低序列复杂性、动态磷酸化模式和结构可变性，因此其结构仍未被很好地理解。我们使用整合结构生物学方法，可视化了 CTD 与 Rtt103 （一种 3'-端 RNA 加工和转录终止因子）形成复合物的结构。Rtt103 通过其长的卷曲螺旋结构形成同源二聚体，并通过其 N 端 CTD 相互作用结构域与磷酸化 CTD 的重复序列紧密结合。CTD-Rtt103 复合物使 CTD 的紧凑无规卷曲结构打开，导致串珠状拓扑结构，其中长杆状的 Rtt103 二聚体定义了整个组装体的拓扑和迁移限制。这些发现强调了 CTD 结构可塑性的重要性，这种可塑性由一组特定的 CTD 结合蛋白模板化。
