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RNAポリメラーゼII転写延長複合体の電子結晶構造
C L Poglitsch1, G D Meredith, A L Gnatt
1Department of Structural Biology, Stanford University School of Medicine, California 94305, USA.
Cell
|September 28, 1999
まとめ
電子結晶学では,活性転写中の酵母RNAポリメラーゼIIの構造を明らかにした. この研究は,DNAが急に曲げられ,酵素の片面に横たわっているチャネル内の核酸を示しています.
科学分野:
- 分子生物学は分子生物学である.
- 構造生物学 構造生物学とは
- バイオケミストリー バイオケミストリー
背景:
- RNAポリメラーゼIIの構造を理解することは,遺伝子転写の解読に不可欠です.
- 以前のモデルでは,DNAがポリメラーゼ内のチャネルを通過することを示唆していた.
研究 の 目的:
- 酵母RNAポリメラーゼII複合体の3D構造を決定する.
- 酵素の活性部位内の核酸の位置と構成を視覚化するために.
主な方法:
- 複雑な構造を解明するために電子結晶学が採用されました.
- 高解像度の画像撮影により,タンパク質と核酸の相互作用を視覚化することができました.
主要な成果:
- 核酸を含むトランスクリプションバブルは,25アングストロームチャンネルを占有しています.
- DNAは,上流と下流の領域の間で顕著な曲線 (約90度) を表しています.
- DNAはポリメラーゼの片面にあり,中央の穴を通らない.
結論:
- 決定された構造は,転写のメカニズムに関する新しい洞察を提供します.
- この発見は,酵母RNAポリメラーゼII活動中のDNAとRNAの位置づけモデルを洗練しています.
関連する概念動画
Eukaryotic RNA Polymerases
RNA Polymerase (RNAP) is conserved in all animals, with bacterial, archaeal, and eukaryotic RNAPs sharing significant sequence, structural, and functional similarities. Among the three eukaryotic RNAPs, RNA Polymerase II is most similar to bacterial RNAP in terms of both structural organization and folding topologies of the enzyme subunits. However, these similarities are not reflected in their mechanism of action.
All three eukaryotic RNAPs require specific transcription factors, of which the...
All three eukaryotic RNAPs require specific transcription factors, of which the...
RNA Polymerase II Accessory Proteins
Proteins that regulate transcription can do so either via direct contact with RNA Polymerase or through indirect interactions facilitated by adaptors, mediators, histone-modifying proteins, and nucleosome remodelers. Direct interactions to activate transcription is seen in bacteria as well as in some eukaryotic genes. In these cases, upstream activation sequences are adjacent to the promoters, and the activator proteins interact directly with the transcriptional machinery. For example, in...
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 Initiation
Initiation is the first step of transcription in eukaryotes. Prokaryotic RNA Polymerase (RNAP) can bind to the template DNA and start transcribing. On the other hand, transcription in eukaryotes requires additional proteins, called transcription factors, to first bind to the promoter region in the DNA template. This binding helps recruit the specific RNAP that can assemble on the DNA and start transcription.
The promoters and enhancers and their accessory proteins allow tight regulation of...
The promoters and enhancers and their accessory proteins allow tight regulation of...
RNA Polymerase II Accessory Proteins
Proteins that regulate transcription can do so either via direct contact with RNA Polymerase or through indirect interactions facilitated by adaptors, mediators, histone-modifying proteins, and nucleosome remodelers. Direct interactions to activate transcription is seen in bacteria as well as in some eukaryotic genes. In these cases, upstream activation sequences are adjacent to the promoters, and the activator proteins interact directly with the transcriptional machinery. For example, in...
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...