関連する実験動画
Updated: Jul 11, 2026

07:27
Direct Restart of a Replication Fork Stalled by a Head-On RNA Polymerase
Published on: April 29, 2010
転写開始の構造的基礎:RNAポリメラーゼホロ酵素-DNA複合体
Katsuhiko S Murakami1, Shoko Masuda, Elizabeth A Campbell
1The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
まとめ
Thermus aquaticus RNAポリメラーゼホロ酵素の結晶構造は,シグマサブユニットがプロモーターDNAとどのように相互作用するかを明らかにします. これは,転写開始とプロモーター認識メカニズムに関する洞察を提供します.
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ポリメラーゼホロ酵素は,バクテリアの転写開始に不可欠です.
- プロモーターの認識を理解することは,遺伝子調節の解読の鍵です.
研究 の 目的:
- プロモーターDNAと複合したThermus aquaticus RNAポリメラーゼホロ酵素の結晶構造を決定する.
- プロモーター認識と転写開始の分子メカニズムを解明する.
主な方法:
- 6.5アングストロムの解像度のX線結晶学.
- 電子密度マップに個々のコンポーネントの高解像度構造を組み込む.
主要な成果:
- プロモーターDNAは,活性サイトチャネルの外にあるホロ酵素表面に結合する.
- シグマサブユニットは,プロモーター要素との全てのシーケンス固有の接触を媒介する.
- トリプトファンや塩基残留を含むシグマの保存された残留物は,DNA結合と定位において重要な役割を果たします.
結論:
- 決定された構造は,ホロ酵素が変数 -10 と -35 の要素を持つプロモーターを認識する方法を説明します.
- 閉じたおよび開いたプロモーター複合体の形成を理解するための構造的基礎を提供します.
関連する概念動画
The Replisome
DNA replication is carried out by a large complex of proteins that act in a coordinated matter to achieve high-fidelity DNA replication. Together this complex is known as the DNA replication machinery or the replisome.
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
Restarting Stalled Replication Forks
DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart, a...
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...
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:
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...
The Replisome
DNA replication is carried out by a large complex of proteins that act in a coordinated matter to achieve high-fidelity DNA replication. Together this complex is known as the DNA replication machinery or the replisome.
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...

