  The electrical conduction properties of G4-DNA are investigated using a
hybrid approach, which combines electronic structure calculations, molecular
dynamics (MD) simulations, and the formulation of an effective tight-binding
model Hamiltonian. Charge transport is studied by computing transmission
functions along the MD trajectories. Though G4-DNA is structurally more stable
than double-stranded DNA (dsDNA), our results strongly suggest that the
potential improvement of the electrical transport properties in the former is
not necessarily related to an increased stability, but rather to the fact that
G4 is able to explore in its conformational space a larger number of
charge-transfer active conformations. This in turn is a result of the
non-negligible interstrand matrix elements, which allow for additional charge
transport pathways. The higher structural stability of G4 can however play an
important role once the molecules are contacted by electrodes. In this case, G4
may experience weaker structural distortions than dsDNA and thus preserve to a
higher degree its conduction properties.
