Base-content dependence of emission enhancements, quantumyields, and lifetimes of cyanine dyes bound to double-strand DNA: Photophysical properties of monomeric and bichromophoric DNA stains
- Georgia State Univ., Atlanta, GA (United States)
- Eastman Kodak Co., Rochester, NY (United States)
- Molecular Probes, Inc., Eugene, OR (United States)
This paper reports fluorescence quantum yield, emission enhancement, and emission lifetime measurements for 10 cyanine dyes complexed to calf thymus DNA (CT-DNA), (dAdT){sub 10}, and (dGdC){sub 6} duplexes. Six of the dyes are linked bichromophores with four cationic charges per molecule, and four are monomers with two cationic charges per molecule. All of the dyes exhibit either bi- or triexponential emission decay kinetics reflecting different dye/ds DNA modes of binding, and the average radiative lifetime for the bichromophores bound to ds DNA is 5.1{+-}0.8 ns. These results are consistent with expectations that binding-induced restriction of torsion about the central methine bridge is responsible for the large emission enhancements of these dyes. Scrutiny of the lengths of average emission lifetime for these 10 dyes on (dAdT){sub 10} and (dGdC){sub 6} duplexes finds that they do not vary as expected if electron transfer (ET) emission quenching were an important process. There are also differences in emission quantum yield between dyes with pyridinium and quinolinium structural components when bound to (dAdT){sub 10} and (dGdC){sub 6} duplexes. These differences are very distinct for the monomeric dyes where pyridinium dyes have 4-fold greater emission yields on (dAdT){sub 10} duplexes and quinolinium dyes have 2-fold greater emission yields on (dGdC){sub 6} duplexes. 68 refs., 7 figs., 6 tabs.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 174262
- Journal Information:
- Journal of Physical Chemistry, Vol. 99, Issue 51; Other Information: PBD: 21 Dec 1995
- Country of Publication:
- United States
- Language:
- English
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