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Updated: Jul 15, 2026
07:44
High-throughput Purification of Affinity-tagged Recombinant Proteins
Published on: August 26, 2012
細菌のRNAポリメラーゼと結合する転写延長因子GreBの構造と機能
Natacha Opalka1, Mark Chlenov, Pablo Chacon
1The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
Cell
|August 14, 2003
まとめ
バクテリアのグリー因子 (GreAとGreB) は,トランスクリプト分裂を誘発することにより,RNAポリメラーゼの転写を強化します. 構造分析は,GreBを明らかにしています.
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:
- 細菌のグレ因子 (GreAとGreB) は,重要な転写延長因子である.
- それらは内在的なRNAポリメラーゼ (RNAP) の内核分解活性を刺激し,新生トランスクリプトを裂く.
- この活動は,転写の障害を克服し,ゲノムの安定性を維持するために不可欠です.
研究 の 目的:
- GreBがRNAP活動と相互作用し,それを刺激する構造的メカニズムを解明する.
- グレー因子によって媒介されるトランスクリプトの割れ方プロセスに関する原子レベルの洞察を提供するためです.
主な方法:
- エシェリキア・コライ*の核RNAPがGreB.に結合した冷凍電子顕微鏡 (冷凍電子顕微鏡) (cryo-EM)
- 螺旋結晶の画像処理で15 Åの解像度を達成する.
- RNAPとGreBの高解像度の結晶構造を冷凍EMマップに挿入する.
- サイト・ディレクテッド・ミュータジェネシス (SITE-DIRECTED MUTAGENESIS) で,特定のGreB残留物の役割を調査する.
主要な成果:
- RNAP-GreB複合体の構造モデルで,RNAP活性サイトチャネルに広がるGreBのN端のコイルドコイルドメインを明らかにしています.
- 触媒作用に不可欠な GreB コイルの先端に保存された酸性残留物の識別.
- このモデルは,以前に観察されたグレ因子活動を説明し,トランスクリプト割れのためのメカニズム的基礎を提供します.
結論:
- GreBは,そのコイルドコイルドメインを通じてRNAP活性部位と直接相互作用し,トランスクリプト分裂を促進します.
- GreBの保存された酸性残留は,RNAP活性部位の修正におけるその触媒的機能に不可欠である.
- この研究は,グレ因子媒介の転写調節の詳細な構造的理解を提供します.
関連する概念動画
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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...
02:35Transcription Elongation Factors
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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...
01:53Bacterial 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:
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01:47Transcription 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...
00:43Bacterial 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...
02:35Transcription 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...