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High-throughput Purification of Affinity-tagged Recombinant Proteins
Published on: August 26, 2012
RNAポリメラーゼIの機能的構造
Claus-D Kuhn1, Sebastian R Geiger, Sonja Baumli
1Gene Center Munich and Center for Integrated Protein Science CIPSM, Department of Chemistry and Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany.
Cell
|December 28, 2007
まとめ
研究者らは,酵母RNAポリメラーゼI (Pol I) の構造を決定し,それがどのようにリボソーム生体生成を開始するかを明らかにした. この構造は,細胞成長の調節に不可欠なユニークなサブユニットと固有のRNA分裂活動を強調しています.
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:
- リボソーム生物生成は真核細胞の成長に不可欠であり,重要な規制ステップとしてRNAポリメラーゼI (Pol I) によってリボソームRNA (rRNA) の合成が行われます.
- Pol Iの構造と機能を理解することは,細胞成長制御メカニズムの解読に不可欠です.
研究 の 目的:
- イーストRNAポリメラーゼI (Pol I) 機能の構造的基礎を解明する.
- トランスクリプションの開始と延長におけるユニークなPol Iサブユニットの役割を調査する.
- Pol I.の固有の酵素活性を特徴づけるために.
主な方法:
- クリオ電子顕微鏡 (cryo-EM) で,14サブユニットの完全酵母Pol I.の12 Å構造を決定する.
- 核酵素構造のホモロジーモデリング.
- A14/43サブコンプレックス構造のX線結晶学.
主要な成果:
- Pol I,A14/43,クランプ,ドックドメインのハイブリッド構造は,開始因子相互作用のためのユニークな表面を明らかにしました.
- Pol Iの特定のサブユニットであるA49とA34.5は,Pol IIのTFIIFに類似して,固有の延長因子として作用するヘテロダイマーを形成します.
- Pol Iは,A12.2のC末端ドメインに依存する固有の3'-RNA分裂活性を示し,rRNA校正と3'-end処理を容易にする.
結論:
- 決定された構造は,Pol I.によるrRNA合成の調節に関する洞察を提供します.
- この発見は,Pol I.による転写開始,延伸,およびRNA処理のための新しいメカニズムを明らかにしています.
- この研究は,リボソームの生体生成と,真核細胞の成長におけるその役割についての理解を深める.
関連する概念動画
Bacterial RNA Polymerase
Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. The multisubunit structure of the bacterial RNAP helps the enzyme to maintain catalytic function, facilitate assembly, interact with DNA and RNA, and self-regulate its activity.
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
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 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...
Bacterial RNA Polymerase
Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. The multisubunit structure of the bacterial RNAP helps the enzyme to maintain catalytic function, facilitate assembly, interact with DNA and RNA, and self-regulate its activity.
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
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...

