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单分子拉伸力实验对DNA解链动力学的研究发现了拉断力分布的宽尾特征,意味着解链动力学速率的含时涨落,即动力学无序现象.本文立足一维广义朗之万方程,描述在拉伸力作用下大分子体系构象态转变动力学,结合分数高斯噪声和幂律摩擦记忆内核,引入构型涨落的亚扩散特征;借助Kramers速率理论,推导含时反应速率k(t,F)、非单指数衰减残存概率分布S(t,F)以及恒速拉伸力作用下的拉断力分布p(F)等,揭示动力学无序效应;将理论应用于DNA解链的单分子拉伸力实验研究,采用漏斗势能模型,拟合不同恒速拉伸力作用下的拉断力分布曲线,估算体系的本征反应速率和势能面特征参数;与Bell公式,以及基于马尔可夫近似的介观统计理论进行系统比较.结果表明,本文建立的动力学无序理论能很好地拟合实验结果,解释单分子拉伸力作用下DNA解链拉断力分布的宽尾特征,揭示了该动力学无序效应与DNA构型慢涨落亚扩散机制的内在关联.
Uniaxial tensile test on the kinetics of DNA melting found that the distribution of the tensile force of the wide tail features, which means that the dissolution kinetic rate of time-dependent fluctuations, that is, kinetic disorder.This article based on one-dimensional generalized Langevin equation describing the conformational state transition kinetics of macromolecule systems under the action of tensile force, combining the fractional Gaussian noise and the power law friction memory kernel, introducing the characteristic of sub-diffusion of configuration fluctuation; using Kramers rate theory, The reaction rate k (t, F), the non-single exponential decay residual probability distribution S (t, F) and the tensile force distribution p (F) Applied to the uniaxial tensile test of DNA unloader, the funnel potential energy model was used to fit the strain distribution curve under different constant-speed tensile forces to estimate the intrinsic reaction rate and the characteristic parameters of potential energy surface. Bell formula and Meso-statistics theory based on Markov approximation were compared systematically.The results show that the kinetic disordered theory established in this paper can well fit the experimental results and explain the effect of single molecule tensile force The wide-tailed feature of the force distribution reveals this The Internal Relationship between Kinetic Disorder Effect and Slow Fluctuation Sub - Diffusion Mechanism in DNA Configuration.