在2.8A分辨率下,核细胞核粒子的晶体结构
K Luger1, A W Mäder, R K Richmond
1Institut für Molekularbiologie und Biophysik, Zürich, Switzerland.
Nature
|September 26, 1997
概括
染色质核细胞核原子的核心粒子.
科学领域:
- 结构生物学是结构生物学.
- 分子遗传学 分子遗传学
- 生物化学 生物化学
背景情况:
- 染色素是DNA和蛋白质的复合体,在真核细胞的细胞核中形成染色体,在基因组组织和调节中起着至关重要的作用.
- 核细胞核粒子是染色体的基本重复单元,由大约146个基对的DNA组成,围绕着一个基因组蛋白八重体包裹.
- 了解核体内DNA和基因组的精确排列对于破译基因调节和DNA可访问性至关重要.
研究的目的:
- 为了阐明核细胞核粒子的原子层结构.
- 详细介绍了组合的基因组蛋白八聚体和DNA的组织围绕它.
- 研究调控基因组-DNA结合的分子相互作用及其对DNA结构的影响.
主要方法:
- 采用X射线晶体学来确定核细胞核粒子的高分辨率三维结构.
- 进行了详细的结构分析,以确定特定的基因组-基因组和基因组-DNA相互作用接口.
- 在超螺旋中对DNA的组织和定位进行了详细的原子研究.
主要成果:
- X射线晶体结构揭示了基因组的原子细节和146个基对DNA的超螺旋组织.
- 基因组-基因组和基因组-DNA相互作用是由基因组折叠域和相关结构元素介导的.
- 基因组氨基末尾延伸到核心粒子之外,可能调解核体间接触.
- 基因组-DNA结合点的不均性导致DNA从理想的超螺旋几何结构中偏离.
结论:
- 核细胞核粒子结构为了解染色体组织提供了详细的分子框架.
- 基斯顿折叠域对于八分体内和DNA结合相互作用都至关重要.
- 基因素尾的灵活性和相互作用表明它们在更高阶染色体结构和调节中的作用.
- DNA路径的变化表明一个动态和适应性的核细胞体结构影响DNA可访问性.
相关概念视频
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...