Nanopore Translocation Dynamics of a Single DNA-Bound Protein
Nanopore Translocation Dynamics of a Single DNA-Bound Protein
复制标题
DOI：
10.1021/nl201541y
复制
发表时间：
2011-07-01
期刊：
影响因子：
10.8
通讯作者：
Anselmetti, Dario
中科院分区：
文献类型：
--
作者：
Spiering, Andre;Getfert, Sebastian;Anselmetti, Dario
我们通过光学镊子和电场（纳米孔力谱）研究了连接到双链DNA上的单个蛋白质分子的易位动力学。我们发现了明显的不对称和延迟力信号，这取决于蛋白质电荷，DNA弹性及其在缓冲液中的反离子筛选。建立了一个理论模型，其中弹性多电解质链上的孤立电荷正在经历非谐波纳米孔电位。其结果与实测力曲线吻合良好，解释了力与外加电场呈线性关系的实验结果，并在前后移位周期中表现出较小的滞后。此外，易位动力学反映了纳米孔中两个相邻状态之间热激活跳跃的随机性，可以用Kramers速率理论充分描述。
We study the translocation dynamics of a single protein molecule attached to a double-stranded DNA that is threaded through a solid-state nanopore by optical tweezers and an electric field (nanopore force spectroscopy). We find distinct asymmetric and retarded force signals that depend on the protein charge, the DNA elasticity and its counterionic screening in the buffer. A theoretical model where an isolated charge on an elastic, polyelectrolyte strand is experiencing an anharmonic nanopore potential was developed. Its results compare very well with the measured force curves and explain the experimental findings that the force depends linearly on the applied electric field and exhibits a small hysteresis during back and forth translocation cycles. Moreover, the translocation dynamics reflects the stochastic nature of the thermally activated hopping between two adjacent states in the nanopore that can be adequately described by Kramers rate theory.