Long-distance charge transport from a guanine radical cation (G(+.)) to a G
-rich sequence is of biological importance. This reaction was studied by se
lective charge injection into a G, monitoring the charge transport to a GGG
sequence by competing H2O-trapping. The efficiency of the charge transport
diminished dramatically with increasing number of A:T base pairs between G
(+.) and GGG. But in DNA strands where G's are located between the G(+.) an
d GGG sequence, long-distance charge transport occurred by a multistep hopp
ing mechanism.