长距离的PELDOR测量对基斯顿核心粒子的测量
Richard Ward1, Andrew Bowman, Hassane El-Mkami
1School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
Journal of the American Chemical Society
|January 14, 2009
概括
研究人员使用位点定向旋转标记和脉冲电子磁共振 (EPR) 来测量 histone octamers 内的距离. 这种技术提供了远程距离测量,揭示了对染色质结构的洞察力.
科学领域:
- 结构生物学 结构生物学
- 生物物理学的生物物理.
- 分子生物学分子生物学
背景情况:
- 核素核粒子是染色素的基本单位.
- 了解染色体结构动力学和功能需要探测其组成部分.
- 由H4,H3,H2A和H2B组成的基因组八体构成核细胞的核心.
研究的目的:
- 通过先进的生物物理技术,探测素八基体的结构和动态.
- 为了确定基斯顿核心粒子内的远程距离.
- 为了评估与晶体结构相比,自旋标记的基因素八合体的结构完整性.
主要方法:
- 位点定向的旋转标签用于将氧化物旋转标签附加到H3基因组.
- 将标记的H3基因组组装成功能性基因组八合体.
- 脉冲电子磁共振 (EPR),特别是PELDOR/DEER实验,用于测量距离.
主要成果:
- 成功完成了PELDOR/DEER对自旋标记的素八度体的实验.
- 在长时间内获得了明确的二极振荡.
- 推导了60-70 Å之间的距离分布,代表了迄今为止生物系统中最长,最明确的测量结果.
- 观察到与既定晶体结构的微小偏差.
结论:
- 与PELDOR/DEER相结合的位点定向旋转标签对于测量生物系统中长距离的有效,比如质子核心粒子.
- 结果提供了关于基斯顿核心粒子结构尺寸的宝贵见解.
- 该技术接近脉冲EPR的距离测量的极限.
相关概念视频
The 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...
The 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...
The 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...
The 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...
The 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...
Chromatin Packaging
Each human somatic cell contains 6 billion base pairs of DNA. Each base pair is 0.34 nm long, meaning each diploid cell contains a staggering 2 meters of DNA. This long DNA strand is packed inside a nucleus measuring only 10-20 microns in diameter with the help of specialized DNA-binding proteins called histones. Together they form a compact DNA-protein complex called chromatin. The chromatin is further compacted into higher-order structures. The highest level of compaction is achieved during...


