転写因子とDNA修復複合体の電子結晶構造,核TFIIH
1Department of Structural Biology, Stanford University School of Medicine, California 94305, USA.
Cell
|September 28, 2000
まとめ
DNA修復とRNAポリメラーゼIIの転写に不可欠な酵母転写因子IIH (TFIIH) を構造的に分析した. 研究者は2D結晶化と電子顕微鏡を用いてその亜単位配置を決定し,コアリング構造を明らかにした.
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:
- 転写因子IIH (TFIIH) は,多亜単位複合体である.
- TFIIHは,RNAポリメラーゼIIの転写と核酸切除DNA修復経路の両方で重要な役割を果たしています.
- TFIIHの構造的組織を理解することは,その機能的メカニズムを明らかにする鍵です.
研究 の 目的:
- 酵母核TFIIH複合体の3次元構造を決定する.
- TFIIH構造内の個々のサブユニットの配置を視覚化します.
- TFIIHコンポーネントの既知の機能的役割と構造的特徴を相関させる.
主な方法:
- コアイーストTFIIHの2D結晶の形成は,リピッドが充電された層に発生する.
- 負染色を用いた2D結晶の電子マイクログラフから difraktionデータを取得.
- TFIIH複合体の3次元の再構築,得られた微分データから.
主要な成果:
- この研究では,酵母TFIIHの構造を約13アングストームの解像度で解明することができました.
- 3D再構築では,TFIIHの個々のサブユニットに対応する明確な密度領域が明らかになりました.
- コア構造は,3つのサブユニット (Tfb1,Tfb2,Tfb3) のリングとして構成され,機能モジュール (Rad3,Ssi1,Ssi2,Kin28) が付属しています.
結論:
- 決定された構造は,酵母TFIIH.の詳細な分子モデルを提供します.
- サブユニットの配置は,異なる機能モジュールが複合体内でどのように統合されているかを明確にします.
- この構造的洞察は,トランスクリプションとDNA修復におけるTFIIHの役割を理解するために不可欠です.
関連する概念動画
02:16Transcription Factors
Tissue-specific transcription factors contribute to diverse cellular functions in mammals. For example, the gene for beta globin, a major component of hemoglobin, is present in all cells of the body. However, it is only expressed in red blood cells because the transcription factors that can bind to the promoter sequences of the beta globin gene are only expressed in these cells. Tissue-specific transcription factors also ensure that mutations in these factors may impair only the function of...
02:02DNA Topoisomerases
Topoisomerases are enzymes that relax overwound DNA molecules during various cell processes, including DNA replication and transcription. These enzymes regulate positive and negative DNA supercoiling without changing the nucleotide sequence. DNA overwinding in a clockwise direction results in positively supercoiled DNA, whereas underwinding in a counterclockwise direction produces negatively supercoiled DNA.
Types and Mechanism of action
Topoisomerases are divided into two main types. Type I...
Types and Mechanism of action
Topoisomerases are divided into two main types. Type I...
02:16Transcription Factors
Tissue-specific transcription factors contribute to diverse cellular functions in mammals. For example, the gene for beta globin, a major component of hemoglobin, is present in all cells of the body. However, it is only expressed in red blood cells because the transcription factors that can bind to the promoter sequences of the beta globin gene are only expressed in these cells. Tissue-specific transcription factors also ensure that mutations in these factors may impair only the function of...
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...
01:30General Transcription Factors
Tissue-specific transcription factors contribute to diverse cellular functions in mammals. For example, the gene for beta globin, a major component of hemoglobin, is present in all cells of the body. However, it is only expressed in red blood cells because the transcription factors that can bind to the promoter sequences of the beta globin gene are only expressed in these cells. Tissue-specific transcription factors also ensure that mutations in these factors may impair only the function of...
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...