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転写の構造的基礎:RNAポリメラーゼIIで2.8アングストームの解像度
P Cramer1, D A Bushnell, R D Kornberg
1Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126, USA.
まとめ
酵母RNAポリメラーゼIIの構造研究は,転写開始に不可欠なクランプを含む4つの移動モジュールを明らかにします. 活性部位の金属イオンとRNA脱出経路も詳細に説明されています.
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は,真核生物の遺伝子転写に不可欠である.
- その構造を理解することは,転写プロセスを解読する鍵です.
- 以前の研究では,RNAポリメラーゼIIで移動式クランプドメインがあることが示された.
研究 の 目的:
- イーストRNAポリメラーゼIIの高解像度構造を決定する.
- 転写の開始と延長の構造的基礎を明らかにする.
- 酵素複合体内の重要な機能的要素を特定する.
主な方法:
- X線結晶学を使用して,2.8と3.1アンストームの解像度で構造を取得しました.
- 異なる結晶形態の比較分析により,移動モジュールが明らかになった.
- 違い フーリエマッピングは,活性部位で金属イオンを特定しました.
主要な成果:
- 酵母RNAポリメラーゼII構造は,振動クランプを含む4つの移動モジュールで構成されています.
- 2.8アングストーム構造のオープンクランプ構成は,プロモーターDNAの侵入を容易にします.
- 活性部位には2つの金属イオンが観察され,そのうちの1つはRNA合成中に交換可能な可能性がある.
- 証拠によると,RNAの脱出は,カルボキシル末端の繰り返し領域の近くで発生し,合成と処理を結びつけるという.
結論:
- 特定された移動モジュール,特にクランプは,転写において重要な役割を果たします.
- 構造的な洞察は,DNA/RNAの相互作用と金属イオン触媒の理解のための基礎を提供します.
- この発見は,RNA合成とRNA処理機械の間の機能的結合を示唆している.
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...
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 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...
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...

