一个ILPR i-motif和一个具有相似机械稳定性的部分折叠结构的共存在单分子水平上被揭示出来
Soma Dhakal1, Joseph D Schonhoft, Deepak Koirala
1Department of Chemistry, Kent State University, Kent, Ohio 44242, USA.
Journal of the American Chemical Society
|June 16, 2010
概括
这项研究使用激光笔研究了DNA中的i-motif结构. 研究人员确定了两种物种,一种是i-motif,并发现两者都可以机械地阻止RNA转录.
科学领域:
- 分子生物学分子生物学
- 生物物理学的生物物理.
- 遗传学 是一个遗传学.
背景情况:
- 在双链DNA中,G四重复是至关重要的,但在互补的丰富的细胞因子区域中的i-动机结构是不太了解的.
- 单分子技术为G四重复体提供了独特的见解,但对i-motifs的类似研究很少.
研究的目的:
- 通过使用激光子来研究在5' - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2序列中形成的i-图案结构.
- 描述这些DNA结构的机械特性和pH依赖性行为.
主要方法:
- 激光子被用来测量轮长度 (DeltaL) 和展开的自由能量 (DeltaG) 的变化.
- 批量实验包括Br(2) 足迹,圆形二重化和热变质证实了这些发现.
- 从pH值5.5到7.0监测了pH值依赖的结构变化.
主要成果:
- 观察到两种不同的物种,DeltaL为10.4nm (分配给i-motif) 和5.1nm (部分折叠结构).
- 随着pH值的增加,i-motif形成显著下降,与已知的行为一致.
- 部分折叠的结构显示了较低的pH敏感度和较低的DeltaG ((展开),表明一个中间状态.
结论:
- 这项研究证实ILPR序列中形成了i-motif和pH不敏感的部分折叠结构.
- 部分折叠的结构似乎是i-motif展开中的中间体,稳定性降低.
- 这两种结构都表现出高的破裂力,表明它们可以机械地阻碍RNA转录.
相关概念视频
Protein Folding
Overview
Protein Folding
Proteins are chains of amino acids linked together by peptide bonds. Upon synthesis, a protein folds into a three-dimensional conformation, critical to its biological function. Interactions between its constituent amino acids guide protein folding, and hence the protein structure is primarily dependent on its amino acid sequence.
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
Protein Structure Is Critical to Its Biological Function
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Molecular Chaperones and Protein Folding
The native conformation of a protein is formed by interactions between the side chains of its constituent amino acids. When the amino acids cannot form these interactions, the protein cannot fold by itself and needs chaperones. Notably, chaperones do not relay any additional information required for the folding of polypeptides; the native conformation of a protein is determined solely by its amino acid sequence. Chaperones catalyze protein folding without being a part of the folded protein.
The...
The...


