Gene Center Munich and Department of Biochemistry, Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany and Department of Biochemistry and Microbiology, Genome British Columbia Protein Centre, University of Victoria, No. 3101-4464 Markham Street, Vancouver Island Technology Park, Victoria, BC V8Z7X8, Canada.
Nucleic Acids Res. 2013 Nov;41(20):9266-73. doi: 10.1093/nar/gkt704. Epub 2013 Aug 11.
The essential core of the transcription coactivator Mediator consists of two conserved multiprotein modules, the head and middle modules. Whereas the structure of the head module is known, the structure of the middle module is lacking. Here we report a 3D model of a 6-subunit Mediator middle module. The model was obtained by arranging crystal structures and homology models of parts of the module based on lysine-lysine cross-links obtained by mass spectrometric analysis. The model contains a central tetramer formed by the heterodimers Med4/Med9 and Med7/Med21. The Med7/Med21 heterodimer is flanked by subunits Med10 and Med31. The model is highly extended, suggests that the middle module is flexible and contributes to a molecular basis for detailed structure-function studies of RNA polymerase II regulation.
转录共激活因子 Mediator 的核心组成部分包括两个保守的多蛋白模块，即头部模块和中部模块。尽管头部模块的结构已为人所知，但中部模块的结构仍不清楚。在这里，我们报告了 Mediator 中部模块的一个 6 亚基 3D 模型。该模型是通过根据通过质谱分析获得的赖氨酸-赖氨酸交联，排列模块部分的晶体结构和同源模型获得的。该模型包含由异二聚体 Med4/Med9 和 Med7/Med21 形成的中央四聚体。Med7/Med21 异二聚体两侧为 Med10 和 Med31 亚基。该模型高度伸展，表明中部模块具有柔性，并为 RNA 聚合酶 II 调控的详细结构-功能研究提供了分子基础。
