Long-lived fluorescence of homopolymeric guanine-cytosine DNA duplexes.

The fluorescence spectrum of the homopolymeric double helix poly(dG) x poly(dC) is dominated by emission decaying on the nanosecond time-scale, as previously reported for the alternating homologue poly(dGdC) x poly(dGdC). Thus, energy trapping over long periods of time is a common feature of GC duplexes which contrast with AT duplexes. The impact of such behaviour on DNA photodamage needs to be evaluated.