正确和不正确的基对合成之间的能量差异解释了高度精确的DNA复制
Andrew C Olson1, Jennifer N Patro, Milan Urban
1Department of Chemistry and Biochemistry, University of Colorado, UCB 215, Boulder, Colorado 80309, USA.
Journal of the American Chemical Society
|January 16, 2013
概括
DNA复制的准确性是由有利的能量驱动的. 直接测量显示,正确的核酸结合的能量差异远大于预期,足以在没有复杂的聚合酶机制的情况下获得高保真度.
科学领域:
- 分子生物学分子生物学
- 生物化学 生物化学
- 遗传学 是一个遗传学.
背景情况:
- 精确的DNA复制对于遗传稳定至关重要.
- 以前对核酸结合能量的估计是间接的.
- 了解DNA忠实性的能量基础是理解聚合酶功能的关键.
研究的目的:
- 直接测量核酸纳入双链DNA (dsDNA) 的自由能量变化 (ΔG(o)).
- 要量化正确和不正确的基对合成之间的能量差异.
- 评估这些能量对整体DNA复制忠实性的贡献.
主要方法:
- 在溶液中直接测量 ΔG 的合.
- 对正确与不正确的核酸结合的能量进行比较.
- 对DNA聚合酶忠实性的能量贡献的分析.
主要成果:
- 正确和不正确的基对合成之间的测量能量差异 (ΔΔG) 显著大于以前认为的 (平均5.2 ± 1.34 kcal mol-1)).
- 仅仅这些能量就足以解释DNA复制的高精度.
- 早期的聚合酶可能依赖于固有的热力学有利性来实现精确的核酸聚合.
结论:
- 正确核酸结合的固有热力学优势是DNA复制精度的主要驱动因素.
- 复杂的校对机制对于早期的聚合物酶可能并不必不可少.
- 这些发现为理解高可靠性DNA和RNA复制提供了热力学基础.
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