  We explore charge transfer in the telomere G-Quadruplex (TG4) DNA
theoretically by the nonequilibrium Green's function method, and reveal the
topological effect of charge transport in TG4 DNA. The consecutive TG4(CTG4) is
semiconducting with 0.2 ~ 0.3eV energy gap. Charges transfers favorably in the
consecutive TG4, but are trapped in the non-consecutive TG4 (NCTG4). The global
conductance is inversely proportional to the local conductance for NCTG4. The
topological structure transition from NCTG4 to CTG4 induces abruptly ~ 3nA
charge current, which provide a microscopic clue to understand the telomerase
activated or inhibited by TG4. Our findings reveal the fundamental property of
charge transfer in TG4 and its relationship with the topological structure of
TG4.
