Diffusion mechanisms of localised knots along a polymer
Diffusion mechanisms of localised knots along a polymer
复制标题
DOI：
10.1209/epl/i2006-10312-5
复制
发表时间：
2006-11-01
期刊：
影响因子：
--
通讯作者：
Sokolov, I. M.
中科院分区：
文献类型：
--
作者：
Metzler, R.;Reisner, W.;Sokolov, I. M.
我们考虑一个局部结沿线性聚合物链的扩散运动。特别是，我们推导出一旦它靠近链的一端，它从链中逃脱之前的平均扩散时间。整个链在任意一端和结位置之间的自我复制，在此期间结具有自由体积，导致扩散时间呈L-3比例；对于足够长的链，亚扩散将进一步增强这一时间。相反，我们提出局部“呼吸”，即结区（KR）及其邻近区域内的局部构象重排，作为附加机制。kr呼吸对扩散时间尺度的贡献仅为二次，类似于L-2，大大加速了结的逃逸，即使对于很长的链也保证了有限的结迁移率。
We consider the diffusive motion of a localised knot along a linear polymer chain. In particular, we derive the mean diffusion time of the knot before it escapes from the chain once it gets close to one of the chain ends. Self-reptation of the entire chain between either end and the knot position, during which the knot is provided with free volume, leads to an L-3 scaling of diffusion time; for sufficiently long chains, subdiffusion will enhance this time even more. Conversely, we propose local "breathing", i.e., local conformational rearrangement inside the knot region (KR) and its immediate neighbourhood, as additional mechanism. The contribution of KR-breathing to the diffusion time scales only quadratically, similar to L-2, speeding up the knot escape considerably and guaranteeing finite knot mobility even for very long chains.