聚胺的自由能量景观重复
Mingchen Chen1, MinYeh Tsai1, Weihua Zheng1
1Center for Theoretical Biological Physics, ‡Department of Bioengineering, and §Department of Chemistry, Rice University , Houston, Texas 77005, United States.
Journal of the American Chemical Society
|October 28, 2016
概括
具有多重胺 (polyQ) 重复的蛋白质聚合物与神经退行性疾病有关. 这项研究揭示了多Q重复的长度如何影响蛋白质结构和聚合,影响疾病的严重程度.
科学领域:
- 生物化学
- 神经科学
- 计算生物学
背景情况:
- 聚胺 (polyQ) 蛋白聚合物是神经退行性疾病的标志,其重复时间与疾病严重程度相关.
- 之前的研究表明,通过核增长聚合,聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚聚.
- 对于多Q重复长度的临界核大小变化的根本原因尚不清楚.
研究的目的:
- 研究多重胺重复长度,单体结构和蛋白质聚合核化机制之间的关系.
- 阐明聚Q聚合过程中关键核大小的因素.
- 提供与神经退行性疾病发病相关的多Q聚合的分子水平理解.
主要方法:
- 使用关联记忆,水介导,结构和能量 (AMWSE) 模型构建聚Q的自由能量景观.
- 分析了多Q重复长度 (Q20,Q26,Q30) 的单体构造和核化路径.
- 通过检查聚氨酸重复的聚合自由能量概况与有利于形的特定位点突变 (PG) 来验证计算预测.
主要成果:
- 较短的多Q (Q20) 优于扩展形状,并与三元核 (n*~3) 开始聚合.
- 较长的多Q (Q30) 更喜欢β-毛形状,导致下坡聚合.
- 中长度的多Q (Q26) 呈现混合单体形式,从而产生不均的核化机制.
结论:
- 聚Q的单体结构严重依赖于重复的长度,影响聚合途径.
- 从扩展到增长多Q长度的β-毛形状的过渡改变了核化机制.
- 这些发现提供了对多Q介导神经退化的分子基础的见解,并与实验观察一致.
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