Theory of DNA translocation through narrow ion channels and nanopores with charged walls.
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.
Hu
Tao
T
Theoretical Physics Institute, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Shklovskii
B I
BI
D001703:Biophysics / Q000379:methods*; D004247:DNA / Q000737:chemistry*; D004277:DNA, Single-Stranded / Q000737:chemistry; D004563:Electrochemistry / Q000379:methods; D007473:Ion Channels / Q000737:chemistry; D007477:Ions; D008954:Models, Biological; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D055672:Static Electricity
D004277:DNA, Single-Stranded; D007473:Ion Channels; D007477:Ions; D004247:DNA