Hu Tao, Shklovskii B I
Theoretical Physics Institute, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2008 Sep;78(3 Pt 1):032901. doi: 10.1103/PhysRevE.78.032901. Epub 2008 Sep 10.
Translocation of a single-stranded DNA molecule through genetically engineered alpha -hemolysin channels with positively charged walls is studied. It is predicted that transport properties of such channels are dramatically different from neutral wild-type alpha -hemolysin channels. We assume that the wall charges compensate a fraction x of the bare charge q_{b} of the DNA piece residing in the channel. Our predictions are as follows. (i) At small concentration of salt the blocked ion current decreases with x . (ii) The effective charge q_{s} of the DNA piece, which is very small at x=0 (neutral channel) grows with x and at x=1 reaches q_{b} . (iii) The rate of DNA capture by the channel grows exponentially with x . Our theory is also applicable to translocation of a double-stranded DNA molecular in narrow solid state nanopores with positively charged walls.
研究了单链DNA分子通过具有带正电壁的基因工程α-溶血素通道的转运。据预测，此类通道的传输特性与中性野生型α-溶血素通道有显著差异。我们假设壁电荷补偿了通道中DNA片段裸电荷(q_{b}) 的一部分(x)。我们的预测如下：（i）在低盐浓度下，阻断离子电流随(x) 减小；（ii）DNA片段的有效电荷(q_{s}) 在(x = 0)（中性通道）时非常小，随(x) 增大，在(x = 1) 时达到(q_{b})；（iii）通道捕获DNA的速率随(x) 呈指数增长。我们的理论也适用于双链DNA分子在具有带正电壁的狭窄固态纳米孔中的转运。
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