| | | | | | | webmail : intra-extra| Accès VPN| Accès IST| Contact
Fluorescence properties of DNA nucleosides and nucleotides: a refined steady-state and femtosecond investigation
D. Onidas, D. Markovitsi, S. Marguet, A. Sharonov, T . Gustavsson, J. Phys. Chem. B, 2002, 106, 11367.
logo_tutelle logo_tutelle 
Fluorescence properties of DNA nucleosides and nucleotides: a refined steady-state and femtosecond investigation

Total fluorescence decay of a 2 × 10-3 M aqueous solution of dC at 330 nm (open circles) fitted with a monoexponential (solid line) and biexponential function (dashed line). The instrumental response function is represented by squares; λex = 267 nm

The room-temperature fluorescence properties of DNA nucleoside and nucleotide aqueous solutions are studied by steady-state and time-resolved spectroscopy. The steady-state fluorescence spectra, although peaking in the near-UV region, are very broad, extending over the whole visible domain. Quantum yields are found to be mostly higher and the fluorescence decays faster than those reported in the literature. The fluorescence spectra of the 2‘-deoxynucleosides are identical to those of the 2‘-deoxynucleotides, with the exception of 2‘-deoxyadenosine, for which a difference in the spectral width is observed. The steady-state absorption and fluorescence spectra do not show any concentration dependence in the range 5 × 10-6 to 2 × 10-3 M. All fluorescence decays are complex and cannot be described by monoexponential functions. From the zero-time fluorescence anisotropies recorded at 330 nm, it is deduced that after excitation at 267 nm the largest modification in the electronic structure is exhibited by 2‘-deoxyguanosine. In the case of purines, the fluorescence decays and quantum yields are the same for 2‘-deoxynucleosides and 2‘-deoxynucleotides. In contrast, for pyrimidines, the fluorescence quantum yields of nucleotides are higher and the fluorescence decays slower as compared to those of the corresponding nucleosides showing that the phosphate moiety affects the excited-state relaxation.

 

 
Fluorescence properties of DNA nucleosides and nucleotides: a refined steady-state and femtosecond investigation

Normalized total fluorescence decays obtained for 2 × 10-3 M aqueous solutions of 2‘-deoxynucleosides (solid circles) and 2‘-deoxynucleotides (open circles) at 330 nm. λex = 267 nm

#1178 - Last update : 01/22 2009

 

Retour en haut