不结合和转录RNA聚合酶III的分子结构
Niklas A Hoffmann1, Arjen J Jakobi1,2, María Moreno-Morcillo1
1European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
Nature
|November 26, 2015
概括
研究人员可视化了RNA聚合酶III (Pol III) 的结构,揭示了其子单元的组织和构造. 这些发现为Pol III如何转录必要的小RNA提供了新的见解.
科学领域:
- 分子生物学
- 结构生物学
- 生物化学
背景情况:
- RNA聚合酶III (Pol III) 转录必要的小结构RNA,包括转移RNA,核糖体5SRNA和结合体U6小核RNA.
- 尽管具有关键作用,但Pol III仍然是最不具有结构特征的真核RNA聚合酶.
研究的目的:
- 确定Saccharomyces cerevisiae Pol III酶及其延长复合物的高分辨率结构.
- 构建一个17个子单元PolIII酶的原子模型.
- 为了获得有关Pol III特异性转录机制的新见解.
主要方法:
- 使用冷电子显微镜 (cryo-EM) 来获得两种形状的Pol III延长复合体 (3.9 Å分辨率) 和apo Pol III的结构 (4.6 和 4.7 Å分辨率).
- 这些重建使得波尔III的17个子单元原子模型的构建成为可能.
主要成果:
- 低温-EM结构显示了C82-C34-C31异构体在茎附近的准确方向.
- 阐明了C53-C37异构体与非模板DNA链相邻的位置,突出了其在转录终结中的作用.
- 阿波波尔III结构具有不同的茎方向和形 (关闭和开放).
结论:
- 这项研究为真核RNA聚合酶III提供了前所未有的原子层结构洞察力.
- 这些发现阐明了小RNA的Pol III特异性转录的结构基础.
- 这些结构揭示了Pol III如何适应其小型转录目标.
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