7-deazaadinine(Z)is an analog of adenine(A)in which the N7 nitrogen atom of the purine ring is substituted by a C-H group(as shown in Figure 1).The effect of replacing A with Z on charge transport through DNA duplex was investigated by the nonequilibrium Greens function method combined with density functional theory.Z not only preserves the same size of natural A base,but also keeps the selectivity of pairing with the natural counterpart thymine(T)base.Moreover,the electronic transport calculations of three-layer stacked base pairs(GAG and GZG)indicate that replacing AT with ZT can dramatically enhance the hole migrate along DNA duplex by adjusting the HOMO energy level of AT to be closer to that of GC.This work may shed some light on potential candidate materials for constructing building blocks of DNA-based nanowires.