2.8 Aの解像度で核細胞核粒子の結晶構造
K Luger1, A W Mäder, R K Richmond
1Institut für Molekularbiologie und Biophysik, Zürich, Switzerland.
Nature
|September 26, 1997
まとめ
クロマチン核細胞核粒子の核粒子である.
科学分野:
- 構造生物学 構造生物学とは
- 分子遺伝学 分子遺伝学
- バイオケミストリー バイオケミストリー
背景:
- クロマチンは,DNAとタンパク質の複合体であり,真核細胞の核内で染色体を形成し,ゲノム組織と調節において重要な役割を果たします.
- 核粒子の核粒子は,クロマチンの基本的繰り返し単位で,ヒストンタンパク質オクターマーの周りに包まれた約146の塩基対のDNAで構成されています.
- 核体内のDNAとヒストンの正確な配置を理解することは,遺伝子調節とDNAアクセシビリティの解読に不可欠です.
研究 の 目的:
- 核粒子の核粒子の原子レベルの構造を解明する.
- ヒストンタンパク質オクターマーの組み立てと,その周りのDNAの組織を詳細に説明します.
- ヒストン-DNA結合を制御する分子相互作用とそのDNA構造への影響を調査する.
主な方法:
- X線結晶学を用いて,核細胞核粒子の高解像度3次元構造を決定した.
- 詳細な構造分析を行い,特定のヒストン-ヒストンおよびヒストン-DNA相互作用インターフェースを特定しました.
- スーパーヘリックス内のDNAの組織と位置づけは,原子の細部まで調べられました.
主要な成果:
- X線結晶構造は,ヒストン八重体組成の原子の詳細と,DNAの146塩基対の超螺旋的な組織を明らかにします.
- ヒストン-ヒストンおよびヒストン-DNAの相互作用は,ヒストン折り領域および関連する構造的要素によって媒介されます.
- ヒストンのアミノ端尾は,核粒子を超えて広がり,潜在的に核細胞間接触を媒介する.
- ヒストン-DNA結合部位の非均一性は,理想的なスーパーヘリックス幾何学からDNAの偏差につながる.
結論:
- 核細胞核粒子の構造は,染色体組織を理解するための詳細な分子枠組みを提供します.
- ヒストン折りドメインは,イントラオクタマー相互作用とDNA結合相互作用の両方にとって重要である.
- ヒストン尾の柔軟性と相互作用は,より高いレベルのクロマチンの構造と調節における役割を示唆しています.
- DNA経路の変異は,DNAアクセシビリティに影響を与えるダイナミックで適応性の高い核細胞構造を示しています.
関連する概念動画
02:33The Nucleosome
DNA in a human cell is almost 2m long and it is packed inside a tiny nucleus that is only a few microns in diameter. The level of compaction of DNA inside the nucleus is astonishing. It is organized into several sequentially higher levels of compaction to fit into such a tiny space. The most compact form of DNA is a chromosome that can be seen under a microscope in a dividing cell.
DNA is wound twice around a protein complex called histone core, that consist of 8 histone proteins. This complex...
DNA is wound twice around a protein complex called histone core, that consist of 8 histone proteins. This complex...
02:10The Nucleosome Core Particle
Nucleosomes are the DNA-histone complex, where the DNA strand is wound around the histone core. The histone core is an octamer containing two copies of H2A, H2B, H3, and H4 histone proteins.
The paradox
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their main responsibility is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. While on the other hand, they must allow polymerase enzymes to access DNA...
The paradox
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their main responsibility is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. While on the other hand, they must allow polymerase enzymes to access DNA...
02:54Nucleosome Remodeling
Nucleosomes are the basic units of chromatin compaction. Each nucleosome consists of the DNA bound tightly around a histone core, which makes the DNA inaccessible to DNA binding proteins such as DNA polymerase and RNA polymerase. Hence, the fundamental problem is to ensure access to DNA when appropriate, despite the compact and protective chromatin structure.
Nucleosome remodeling complex
Eukaryotic cells have specialized enzymes called ATP-dependent nucleosome remodeling enzymes. These enzymes...
Nucleosome remodeling complex
Eukaryotic cells have specialized enzymes called ATP-dependent nucleosome remodeling enzymes. These enzymes...
02:33The Nucleosome
DNA in a human cell is almost 2m long and it is packed inside a tiny nucleus that is only a few microns in diameter. The level of compaction of DNA inside the nucleus is astonishing. It is organized into several sequentially higher levels of compaction to fit into such a tiny space. The most compact form of DNA is a chromosome that can be seen under a microscope in a dividing cell.
DNA is wound twice around a protein complex called histone core, that consist of 8 histone proteins. This complex...
DNA is wound twice around a protein complex called histone core, that consist of 8 histone proteins. This complex...
01:19The Nucleosome
Human DNA is almost two meters long. However, it is compressed inside a tiny nucleus measuring only a few microns in diameter. To make this degree of compaction possible, DNA is organized into several sequential levels so that it can fit into such a tiny space. The most compact form of DNA is a chromosome that can be seen under a microscope in a dividing cell.
In a chromosome, DNA is wound twice around a protein complex called a histone octamer core, which consists of 8 histone proteins. This...
In a chromosome, DNA is wound twice around a protein complex called a histone octamer core, which consists of 8 histone proteins. This...
01:12The Nucleosome Core Particle
Nucleosomes are the DNA-histone complex, where the DNA strand is wound around the histone core. The histone core is an octamer containing two copies of H2A, H2B, H3, and H4 histone proteins.
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their primary aim is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. On the other hand, they must allow polymerase enzymes to access histone-bound DNA during...
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their primary aim is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. On the other hand, they must allow polymerase enzymes to access histone-bound DNA during...