三价稀土金属共因子赋予快速的NP-DNA聚合酶活性
Victor S Lelyveld1,2, Ziyuan Fang1,2,3, Jack W Szostak1,2,3,4,5,6
1Center for Computational and Integrative Biology, Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA.
概括
研究人员通过识别优异的金属离子辅因子,增强了非自然的N3'→P5'胺酸 (NP) DNA合成. 与标准的 (II) 辅因子相比, (III) 显著增加了NP-DNA的形成.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 合成生物学 合成生物学
背景情况:
- DNA聚合酶通常使用双金属离子机制合成二键.
- 不自然的N3'→P5'胺酸 (NP) 键可以使用工程DNA聚合酶形成,但合成效率低.
- 原生两金属离子机制被认为对高效的酸转移至关重要.
研究的目的:
- 阐明由突变DNA聚合酶催化NP-DNA合成的机制.
- 确定可以提高NP-DNA合成速度和效率的金属离子辅助因子.
- 为了比较不同金属离子在促进非自然胺酸键形成中的催化活性.
主要方法:
- 时间分辨率的X射线晶体学用于在NP-DNA合成过程中可视化活性部位.
- 同位素和元素效应研究探讨金属离子辅因子的作用.
- 动态分析以量化NP-DNA合成通过各种金属的增强.
主要成果:
- 与 ((II) 辅因子的NP-DNA合成涉及到活性位点中的单个金属离子,导致动力学减慢.
- 对于NP-DNA合成而言,一种单金属离子机制的效率低于原生双金属离子机制.
- 三价金属,特别是,显著提高NP-DNA合成率 (>100倍超过).
- 扫 (Scandium) 能够合成长度高达100个核酸的NP-DNA链.
结论:
- 低效的NP-DNA与的合成是由于一个低于最佳的单金属离子激活机制.
- 三价金属,特别是,可以有效地取代本地二价,增强NP-DNA合成.
- 这一发现为改进合成生物学工具和新型核酸类似物开辟了道路.
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