Luo Kaifu, Ala-Nissila Tapio, Ying See-Chen, Bhattacharya Aniket
Physics Department, Technical University of Munich, D-85748 Garching, Germany.
Phys Rev E Stat Nonlin Soft Matter Phys. 2008 Dec;78(6 Pt 1):061918. doi: 10.1103/PhysRevE.78.061918. Epub 2008 Dec 19.
Using Langevin dynamics simulations, we investigate the influence of polymer-pore interactions on the dynamics of biopolymer translocation through nanopores. We find that an attractive interaction can significantly change the translocation dynamics. This can be understood by examining the three components of the total translocation time tau approximately tau1+tau2+tau3 corresponding to the initial filling of the pore, transfer of polymer from the cis side to the trans side, and emptying of the pore, respectively. We find that the dynamics for the last process of emptying of the pore changes from nonactivated to activated in nature as the strength of the attractive interaction increases, and tau3 becomes the dominant contribution to the total translocation time for strong attraction. This leads to nonuniversal dependence of tau as a function of driving force and chain length. Our results are in good agreement with recent experimental findings, and provide a plausible explanation for the different scaling behavior observed in solid state nanopores vs that for the natural alpha-hemolysin channel.
通过朗之万动力学模拟，我们研究了聚合物 - 孔相互作用对生物聚合物通过纳米孔转运动力学的影响。我们发现，吸引相互作用会显著改变转运动力学。这可以通过考察总转运时间(\tau\approx\tau_1 + \tau_2 + \tau_3)的三个组成部分来理解，它们分别对应于孔的初始填充、聚合物从顺式侧转移到反式侧以及孔的排空。我们发现，随着吸引相互作用强度的增加，孔排空的最后一个过程的动力学性质从非活化变为活化，并且对于强吸引力，(\tau_3)成为总转运时间的主要贡献因素。这导致了(\tau)对驱动力和链长的非普适依赖性。我们的结果与最近的实验发现高度吻合，并为固态纳米孔与天然α - 溶血素通道中观察到的不同标度行为提供了合理的解释。
