通过量子力学/分子力学自由能量模拟探讨对关氨酸-丁氨酸错配的环境影响
Pengfei Li1, Atul Rangadurai2, Hashim M Al-Hashimi2
1Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States.
Journal of the American Chemical Society
|May 28, 2020
概括
基因组分离会产生错配,可能导致突变. 这项研究通过计算检查了不同环境中的关氨酸-丁氨酸 (G-T) 错配对的分离,揭示了对G-T错配对稳定性和反应机制的重大环境影响.
科学领域:
- 生物化学
- 计算化学
- 分子生物学
背景情况:
- DNA 基可以形成不稳定的复合体形式,导致像关氨酸-氨酸 (G-T) 这样的错误配对.
- 这些G-T不匹配与DNA突变和复制错误有关.
- 之前的研究表明环境因素会影响G-T错配种群.
研究的目的:
- 通过计算来研究环境对G-T误对复合的影响.
- 在各种环境中确定G-T共聚的自由能量路径和障碍.
- 阐明DNA聚合酶活性位点内分离的机制差异.
主要方法:
- 混合量子力学/分子力学 (QM/MM) 自由能量模拟.
- 计算出分体化过程中的最小自由能量路径.
- 在水溶液中分析G-T复合和DNA聚合酶λ变体.
主要成果:
- 环境因素显著影响G-T错配反应的自由能量和障碍.
- 在溶液和DNA复合物中,淘米化具有内源性,但在聚合酶中略有外源性.
- 聚合酶环境,特别是Arg517和Asn513的残留物,可以静电稳定G-T*不对.
- 在聚合酶和其他环境中,质子转移反应的顺序不同.
结论:
- 当地环境对G-T误对热力学,动力学和复合机制产生重大影响.
- 这些发现支持在DNA聚合酶作用过程中发生G-T误对分离的模型.
- 了解这些过程对于理解DNA忠实性和突变起源至关重要.
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