関連する実験動画
Updated: Jul 31, 2026
09:26
Reconstitution of Nucleosomes with Differentially Isotope-labeled Sister Histones
Published on: March 26, 2017
Tetrahymena GCN5がコエンザイムAとヒストンH3ペプチドに結合する構造
J R Rojas1, R C Trievel, J Zhou
1The Wistar Institute, Department of Chemistry, University of Pennsylvania, Philadelphia 19104, USA.
Nature
|September 15, 1999
まとめ
テトラヒメナGCN5 (tGCN5) のようなヒストンアセチルトランスフェラーゼ (HAT) 酵素は,遺伝子活性化に不可欠です. 構造研究は,tGCN5がヒストロンとコエンザイムA (CoA) を結合して遺伝子発現を調節する方法を示しています.
科学分野:
- バイオケミストリー バイオケミストリー
- 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
背景:
- 遺伝子の活性化には,クロマチンの抑制を緩和するタンパク質が含まれます.
- 核ヒストンアセチルトランスフェラーゼ (HAT) 酵素は,クロマチンの不安定化を遺伝子活性化と結びつける.
- HATはヒストンライシン残基をアセチル化し,転写活性化剤のDNAアクセスを促進します.
研究 の 目的:
- テトラヒメナGCN5 (tGCN5) HATドメインの高解像度結晶構造を決定する.
- コエンザイムA (CoA) とヒストンH3ペプチドの結合メカニズムを解明する.
- tGCN5.5の触媒機構を理解するために.
主な方法:
- 高解像度構造を入手するために,X線結晶学を用いた.
- 新生tGCN5,tGCN5/アセチル-CoA複合体,CoAとヒストンH3ペプチドを含むtGCN5の構造を決定した.
主要な成果:
- ヒストンの結合特異性は,G-K-X-P認識配列を持つランダムなコイル構造で明らかにされました.
- コエンザイムA (CoA) は,ヒストン結合のための酵素の方向転換に不可欠であることが判明しました.
- カタリシスには,グルタミン酸の一般塩基と骨幹アミドによる水媒介の陽子抽出が含まれます.
結論:
- 構造データはヒストンアセチルトランスフェラーゼ (HAT) の機能と調節に関する洞察を提供します.
- N-アセチルトランスフェラーゼの間で,CoA結合と触媒の保存された構造的枠組みが存在します.
- 基板特有の結合領域の変動は,酵素多様性のメカニズムを示唆しています.
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...
02:32Histone Modification
The histone proteins have a flexible N-terminal tail extending out from the nucleosome. These histone tails are often subjected to post-translational modifications such as acetylation, methylation, phosphorylation, and ubiquitination. Particular combinations of these modifications form “histone codes” that influence the chromatin folding and tissue-specific gene expression.
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...
02:30Histone Variants at the Centromere
Histone variants are the histone proteins with structural and sequence variations. These variants may be regarded as “mutant” forms that replace their canonical histone counterparts in the nucleosomes. Specific post-translational modifications on the histone variants enable further chromatin complexity and regulate tissue-specific gene expression. The most common histone variants are from histone H2A, H2B, and linker histone H1 families. However, several variants of histone H3 variants are also...
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...