转录暂停在细菌中的结构基础
Albert Weixlbaumer1, Katherine Leon, Robert Landick
1The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
Cell
|February 5, 2013
概括
RNA聚合酶 (RNAPs) 暂停对于基因调节和终止至关重要. 我们确定了暂停RNAP延长复合体的晶体结构,揭示了抑制核酸添加和辅助终止的构造.
科学领域:
- 分子生物学分子生物学
- 生物化学 生物化学
- 结构生物学 结构生物学
背景情况:
- 多子单元RNA聚合酶 (RNAPs) 的转录暂停是调节基因表达和转录终止在生命的所有领域的基本机制.
- 这种暂停被认为源于一个共同的元素暂停状态,阻碍了核酸的添加.
- 了解这种暂停状态的结构基础是阐明基因调节和终止过程的关键.
研究的目的:
- 阐明RNA聚合酶中元素暂停状态的结构基础.
- 要了解这种暂停状态如何抑制催化活动并促进转录终止.
主要方法:
- 在X射线晶体学.
- 确定Thermus RNAP元素暂停延长复合体 (ePECs) 的三个晶体结构.
主要成果:
- 晶体结构揭示了在ePEC中的一致的松散,开放的RNAP构造.
- 这种形状是由于在转位过程中无法重新建立DNA接触而产生的.
- 观察到一个扭曲的桥螺旋螺旋体以固态阻断RNAP活性部位,抑制催化活性.
结论:
- 已识别的RNAP构造为暂停期间抑制的核酸添加提供了一个结构性的解释.
- 这种元素暂停状态是RNA毛稳定和转录终止的关键中间体.
- 这些发现为了解暂停,RNA结构和终止机制之间的相互作用提供了一个框架.
相关概念视频
Transcription Elongation Factors
Transcription elongation is a dynamic process that alters depending upon the sequence heterogeneity of the DNA being transcribed. Hence, it is not surprising that the elongation complex's composition also varies along the way while transcribing a gene.
The transcription elongation is regulated via pausing of RNA polymerase on several occasions during transcription. In bacteria, these halts are necessary because the transcription of DNA into mRNA is coupled to the translation of that mRNA into a...
The transcription elongation is regulated via pausing of RNA polymerase on several occasions during transcription. In bacteria, these halts are necessary because the transcription of DNA into mRNA is coupled to the translation of that mRNA into a...
Transcription Attenuation in Prokaryotes
Transcriptional attenuation occurs when RNA transcription is prematurely terminated due to the formation of a terminator mRNA hairpin structure. Bacteria use these hairpins to regulate the transcription process and control the synthesis of several amino acids including histidine, lysine, threonine, and phenylalanine. Transcription attenuation takes place in the non-coding regions of mRNA.
There are several different mechanisms used to attenuate transcription. In ribosome mediated...
There are several different mechanisms used to attenuate transcription. In ribosome mediated...
Bacterial Transcription
RNA polymerase (RNAP) carries out DNA-dependent RNA synthesis in both bacteria and eukaryotes. Bacteria do not have a membrane-bound nucleus. So, transcription and translation occur simultaneously, on the same DNA template.
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
Transcription Elongation Factors
Transcription elongation is a dynamic process that alters depending upon the sequence heterogeneity of the DNA being transcribed. Hence, it is not surprising that the elongation complex's composition also varies along the way while transcribing a gene.
The transcription elongation is regulated via pausing of RNA polymerase on several occasions during transcription. In bacteria, these halts are necessary because the transcription of DNA into mRNA is coupled to the translation of that mRNA into a...
The transcription elongation is regulated via pausing of RNA polymerase on several occasions during transcription. In bacteria, these halts are necessary because the transcription of DNA into mRNA is coupled to the translation of that mRNA into a...
Transcription in Prokaryotes
Transcription is a highly regulated process that converts genetic information into RNA molecules. The transcription cycle is divided into three key stages: initiation, elongation, and termination, each driven by specific molecular mechanisms.Initiation of TranscriptionIn bacteria, transcription begins when the RNA polymerase core enzyme associates with a sigma factor to form a holoenzyme. For example, the E. coli sigma factor called σ70 forms a holoenzyme, which recognizes the -10 (Pribnow box)...
Coordination of Gene Expression Processes in Bacteria
The DNA replication, transcription, and translation processes are intricately coupled in bacteria, allowing efficient gene expression and rapid protein synthesis. While this physical and functional coordination is advantageous, it introduces challenges that bacteria overcome through specific regulatory mechanisms.Coupling of Replication, Transcription, and TranslationThe coupling of replication, transcription, and translation is a hallmark of bacterial gene expression. As the replisome unwinds...


