Air Force Research Laboratory, Wright-Patterson Air Force Base, OH, 45433, USA.
Biomolecular and Materials Interface Research Group, Interdisciplinary Biomedical Research Centre, School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK.
Nat Commun. 2020 Nov 2;11(1):5517. doi: 10.1038/s41467-020-19233-7.
A fundamental problem in thermodynamics is the recovery of macroscopic equilibrated interaction energies from experimentally measured single-molecular interactions. The Jarzynski equality forms a theoretical basis in recovering the free energy difference between two states from exponentially averaged work performed to switch the states. In practice, the exponentially averaged work value is estimated as the mean of finite samples. Numerical simulations have shown that samples having thousands of measurements are not large enough for the mean to converge when the fluctuation of external work is above 4 kT, which is easily observable in biomolecular interactions. We report the first example of a statistical gamma work distribution applied to single molecule pulling experiments. The Gibbs free energy of surface adsorption can be accurately evaluated even for a small sample size. The values obtained are comparable to those derived from multi-parametric surface plasmon resonance measurements and molecular dynamics simulations.
热力学中的一个基本问题是从实验测量的单分子相互作用中恢复宏观平衡相互作用能。雅可比等式为从对状态进行切换所做的指数平均功中恢复两个状态之间的自由能差提供了理论基础。实际上，指数平均功值被估计为有限样本的平均值。数值模拟表明，当外部功的涨落大于 4 kT 时，即使有数千个测量样本，平均值也不足以收敛，而在生物分子相互作用中很容易观察到这种情况。我们报告了第一个应用于单分子拉伸实验的统计伽马功分布的例子。即使对于较小的样本量，也可以准确评估表面吸附的吉布斯自由能。得到的值与从多参数表面等离子体共振测量和分子动力学模拟得出的值相当。
