在LINE-1ORF2p中核基转移的机制由QM/MM模拟揭示出来
Igor V Polyakov1, Kirill D Miroshnichenko1, Tatiana I Mulashkina1,2
1Chemistry Department, Lomonosov Moscow State University, 119991 Moscow, Russia.
International journal of molecular sciences
|September 13, 2025
概括
长间隔元素-1 (L1) 逆转录酶 (RT) 使用单个Mg2+离子进行DNA延长. 这项研究揭示了一步核类转移机制,没有第二个催化金属离子.
科学领域:
- 分子生物学分子生物学
- 生物化学 生物化学
- 基因组学就是基因组学.
背景情况:
- 长间隔元素-1 (L1) 逆转移子是人类基因组的重要组成部分.
- 在L1逆转换中的关键酶ORF2p具有内核酶和逆转录酶活动.
- 现有的结构数据显示,在逆转录酶活性位点中,单个Mg2+离子存在,与典型的DNA聚合酶机制不同.
研究的目的:
- 研究L1逆转移子ORF2p.p.的DNA延长机制.
- 阐明金属离子在逆转录酶活性部位中的作用.
- 为了使结构发现与酶活性相协调.
主要方法:
- 结合量子力学 (QM) 和分子力学 (MM) 模拟使用PBE0-D3/6-31G**和CHARMM.
- 有偏见的雨采样分子动力学模拟.
- 雨集成计算核基转移反应的自由能量概况.
主要成果:
- DNA延长反应通过单步核基转移进行.
- 为反应确定了15.1 ± 0.8 kcal/mol的自由能量屏障.
- 产品稳定性计算为7.8 ± 1.2 kcal/mol. 在7.8 ± 1.2 kcal/mol.
- 该机制涉及协调的核友性攻击和无需第二个催化金属离子的质子转移.
- 估计的速率常数为~60 s-1,与已知的RT动力学相一致.
结论:
- L1 ORF2p逆转录酶利用了一个独特的催化机制,涉及单个Mg2+离子.
- 反应通过解离机制进行,挑战了DNA聚合酶的正规两金属离子模型.
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