从NMR化学转移扰动中确定的蛋白质介电常数
Predrag Kukic1, Damien Farrell, Lawrence P McIntosh
1School of Biomolecular and Biomedical Science, Centre for Synthesis and Chemical Biology, UCD Conway Institute, University College Dublin , Belfield, Dublin 4, Ireland.
Journal of the American Chemical Society
|October 16, 2013
概括
这项研究通过使用NMR化学转移扰动测量电场来确定蛋白质的最佳介电常数. 这些发现表明了蛋白质介电常数的新内在值,这对于精确的静电计算至关重要.
科学领域:
- 生物物理学的生物物理.
- 结构生物学 结构生物学
- 计算化学计算化学
背景情况:
- 准确的静电计算对于理解蛋白质结构功能关系至关重要.
- 关于蛋白质模型的适当介电常数 (ε(eff) 和 ε(p)) 存在长期的争论.
- 当前介电常数值是经验和间接测量的,限制了它们的一般适用性.
研究的目的:
- 为了确定蛋白质的最佳介电常数 (ε(eff) 和 ε(p)).
- 使用NMR化学转移扰动 (CSP) 直接测量蛋白质电场.
- 为了建立更准确和可转移的介电常数用于静电建模.
主要方法:
- 测量了14种不同的蛋白质的CSP,以表征电场.
- 应用了库伦定律来将CSP与介电常数相关联.
- 使用有限差异Poisson-Boltzmann计算进行界面分析.
主要成果:
- 在使用库伦定律时,最优的 ε (((eff) 范围为3到13,平均值为6.5.
- 通过Poisson-Boltzmann计算考虑水-蛋白界面时,发现最优的 ε (p) 是 3 (范围为 2 - 5).
- 确定的3的ε(p) 与蛋白质粉末测量的值保持一致,与用于热力学计算的更高值不同.
结论:
- 对于折叠的蛋白质来说,3的衍生的介电常数很可能是内在的和可转移的,准确地反映电场.
- 这个值与基于热力学参数的模型中使用的值有很大的不同.
- 这些发现为基于蛋白质结构的静电计算提供了更坚实的基础.
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