Gene Center and Department of Biochemistry, Center for Integrated Protein Science Munich, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany.
Nucleic Acids Res. 2011 Aug;39(14):6291-304. doi: 10.1093/nar/gkr229. Epub 2011 Apr 15.
Mediator is a multiprotein co-activator of RNA polymerase (Pol) II transcription. Mediator contains a conserved core that comprises the 'head' and 'middle' modules. We present here a structure-function analysis of the essential Med11/22 heterodimer, a part of the head module. Med11/22 forms a conserved four-helix bundle domain with C-terminal extensions, which bind the central head subunit Med17. A highly conserved patch on the bundle surface is required for stable transcription pre-initiation complex formation on a Pol II promoter in vitro and in vivo and may recruit the general transcription factor TFIIH. The bundle domain fold is also present in the Mediator middle module subcomplex Med7/21 and is predicted in the Mediator heterodimers Med2/3, Med4/9, Med10/14 and Med28/30. The bundle domain thus represents a common building block that has been multiplied and functionally diversified during Mediator evolution in eukaryotes.
中介体是 RNA 聚合酶 (Pol) II 转录的多蛋白共激活因子。中介体包含一个保守的核心，由“头部”和“中部”模块组成。我们在这里对必需的 Med11/22 异二聚体进行了结构-功能分析，它是头部模块的一部分。Med11/22 形成一个保守的四螺旋束结构域，带有 C 端延伸，与中央头部亚基 Med17 结合。在体外和体内，束表面上高度保守的补丁对于 Pol II 启动子上稳定的转录起始复合物的形成是必需的，并且可能募集一般转录因子 TFIIH。束结构域折叠也存在于中介体中间模块亚基复合物 Med7/21 中，并在中介体异二聚体 Med2/3、Med4/9、Med10/14 和 Med28/30 中预测。因此，束结构域代表一个共同的构建块，在真核生物中介体的进化过程中已经被复制和功能多样化。
