预催化人类结合体的冷-电磁结构为激活准备
Karl Bertram1, Dmitry E Agafonov2, Olexandr Dybkov2
1Department of Structural Dynamics, MPI for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
Cell
|August 8, 2017
概括
这项研究揭示了催化前人类结合体 (B复合体) 的3D结构. 观察到不同于酵母的关键蛋白质重组,为结合体激活提供了洞察力.
科学领域:
- 分子生物学
- 结构生物学
- 生物化学
背景情况:
- 结合体是基因表达所必需的动态分子机器.
- 在早期激活阶段了解它的结构对于破译它的功能至关重要.
- 对于催化前结合体复合体的结构数据有限.
研究的目的:
- 确定人体前催化体B复合体的3D结构.
- 为了阐明关键组件在拼接组件组件中的结构重组.
- 确定人类和酵母之间的早期结合体激活的差异.
主要方法:
- 用冷电子显微镜 (cryo-EM) 获得高分辨率的3D结构数据.
- 对蛋白质-RNA相互作用和B复合体内的构造变化的分析.
- 用酵母结合体进行比较结构分析.
主要成果:
- 获得了人类结合体B复合体的详细3D冷EM结构.
- 在整合过程中观察到U4 / U6. U5三snRNP蛋白的显著重新排列.
- 鉴定出一种独特的前催化形状,包括5'拼接点结合口袋,与酵母不同.
结论:
- 该结构揭示了催化激活前的结合体组织方式.
- 特定的蛋白质动态,如Brr2重组和B特定的蛋白质作用,对于结合体激活至关重要.
- 人类和酵母结合体激活途径具有显著的结构差异.
相关概念视频
RNA Splicing
60.9K
Splicing is the process by which eukaryotic RNA is edited before its translation into protein. The RNA strand transcribed from eukaryotic DNA is called the primary transcript. The primary transcripts that become mRNAs are called precursor messenger RNAs (pre-mRNAs). Eukaryotic pre-mRNA contains alternating sequences of exons and introns. Exons are nucleotide sequences that code for proteins, whereas introns are the non-coding regions. In RNA splicing, introns are removed and exons are bonded...
60.9K
Chromatin Structure Regulates pre-mRNA Processing
8.3K
In eukaryotic cells, nascent mRNA transcripts need to undergo many post-transcriptional modifications to reach the cell cytoplasm and translate into functional proteins. For a long time, transcription and pre-mRNA processing were considered two independent events that occur sequentially in the cell. However, it has now been well established that transcription and pre-mRNA processing are two simultaneous processes that are precisely regulated inside the cell.
The chromatin structure, especially...
The chromatin structure, especially...
8.3K
Chromatin Structure and RNA Splicing
3.5K
3.5K
Pre-mRNA Processing: RNA Splicing
7.1K
7.1K
tRNA Activation
8.7K
8.7K
tRNA Activation
23.5K
Aminoacyl-tRNA synthetases are present in both eukaryotes and bacteria. Though eukaryotes have 20 different aminoacyl-tRNA synthetases to couple to 20 amino acids, many bacteria do not have genes for all of these aminoacyl-tRNA synthetases. Despite this, they still use all 20 amino acids to synthesize their proteins. For instance, some bacteria do not have the gene encoding the enzyme that couples glutamine with its partner tRNA. In these organisms, one enzyme adds glutamic acid to all of the...
23.5K


