ヘクサソームとオクタソームで構成される重複する二核細胞体の結晶構造
Daiki Kato1, Akihisa Osakabe1, Yasuhiro Arimura1
1Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
Science (New York, N.Y.)
|April 15, 2017
まとめ
クロマチンの改造により,ヘクサソーム・ニュクレオソームがオクタソーム・ニュクレオソームと接触する二重重複のニュクレオソームが生成される. この構造はDNAプロセス中の 核細胞の再定位の洞察を示しています
科学分野:
- 分子生物学
- 構造生物学
- 遺伝学
背景:
- 核細胞は真核生物のDNA包装の基本単位である.
- クロマチンの改造酵素は,スイッチサクロース非発酵 (SWI/SNF) のように,ニュクレオソームの位置を動的に変化させる.
- 核細胞の再定位は,重複する二核細胞のような中間構造の形成につながります.
研究 の 目的:
- 超重複する二核子の高解像度結晶構造を決定する.
- クロマチンの改造過程におけるヌクレオソーム-ヌクレオソーム相互作用の構造的基礎を解明する.
- ニュクレオソームの再定位の仕組みについての洞察を提供するためです.
主な方法:
- X線結晶学
- 高解像度構造の決定 (3.14アングストーム)
- タンパク質-DNA複合体の構造分析
主要な成果:
- オーバーラップする二核細胞体の結晶構造は3. 14アングストームの解像度で決定された.
- 構造は,ヘクサソーム核体 (ヒストンヘクサマー) と正規のオクタソーム核体 (ヒストンオクタマー) の間の密接な関連を示している.
- およそ250の塩基対のDNAが3回転で左手に巻き込まれていて,2つの核群の間のリンクア DNAセグメントが欠けている.
結論:
- 決定された構造は,重複する二核体中間体の詳細な分子視点を提供します.
- この構造は,クロマチンのリモデラーによる核細胞の再定位のメカニズムを理解するために重要な情報を提供します.
- この発見は,クロマチンのダイナミクスと遺伝子調節のより広範な理解に貢献します.
関連する概念動画
02:42Ionic Crystal Structures
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
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...
02:33The 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...