Xue-Feng Wang, Tapash Chakraborty, J. Berashevich
The effect of mispair on charge transport in a DNA of sequence
(GC)(TA)_N(GC)_3 connected to platinum electrodes is studied using the
tight-binding model. With parameters derived from ab initio density functional
result, we calculate the current versus bias voltage for DNA with and without
mispair and for different numbers of (TA) basepairs N between the single and
triple (GC) basepairs. The current decays exponentially with $N$ under low bias
but reaches a minimum under high bias when a multichannel transport mechanism
is established. A (GA) mispair substituting a (TA) basepair near the middle of
the (TA)_N sequence usually enhances the current by one order due to its low
ionization energy but may decrease the current significantly when an
established multichannel mechanism is broken.
View original:
http://arxiv.org/abs/1202.1849
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