Abstract:
There is increasing evidence that DNA can support a considerable degree of charge
transport along the strand by hopping of holes from one base to another, and that this
charge transport may be relevant to DNA regu ation, damage detection and repair. A
surprisingly useful amount of insight can be gained from tne construction of simple
tight-binding models of charge transport , which can be investigated using the
transfer-matrix method. The data thus obtained indicate a correlation between DNA
charge-transport properties and the locations o f cancerous mutation; We review
models for DNA charge transport and their extension to include more physically
realistic diagonal-hopping terms.
In the present paper, we will investigate electronic transport in DNA by (i)
introducing what appears to be the most appropriate tight-binding model of DNA and
(ii) studying its transport characteristics for a large set of cancer-related genes given
by the human genome mutation database.
We find that (i) the conductance o f hot spots of caneerous mutations is smaller than
that of other sites, (ii) on average the cancerous mufations yield smaller changes of
the charge-transport in contrast with noncancerous mutations, (iii) the tendency in (ii)
is stronger in the set of highly cancerous mutations with occurrence frequency > 10.
These results suggest a possible scenario of how cancerous mutations could
circumvent the DNA-damage-repair mechanism and survive to yield carcinogenesis.
Our analysis is however only valid in a statistical sense since occasional
noncancerous mutations are found to yield weak change of charge-transport. For
these, other DNA repair processes should exist so that the DNA-damage repair might
not solely uses a charge-transport-based criterion. Still, our results exhibit an
intriguing and new correlation between the electronic structure o f DNA hot spots and
the damage-repair process..
