TY - JOUR
T1 - Ultrafast transient-absorption and steady-state fluorescence measurements on 2-aminopurine substituted dinucleotides and 2-aminopurine substituted DNA duplexes
AU - Larsen, Olaf F.A.
AU - Van Stokkum, Ivo H.M.
AU - De Weerd, Frank L.
AU - Vengris, Mikas
AU - Aravindakumar, Charuvila T.
AU - Van Grondelle, Rienk
AU - Geacintov, Nicholas E.
AU - Van Amerongen, Herbert
PY - 2004/1/7
Y1 - 2004/1/7
N2 - Ultrafast transient-absorption and steady-state fluorescence measurements have been performed on dinucleotides comprising the fluorescent adenine analogue 2-aminopurine and guanine, adenine, cytosine, thymine or hypoxanthine, respectively. Two oligodeoxyribonucleotide duplexes that were site-selectively substituted with a single 2-aminopurine moiety were also studied. A strong quenching of the steady-state fluorescence was observed in all samples. The transient-absorption spectra were remarkably similar to those of the isolated 2-aminopurine (Larsen et al.; O. F. A. Larsen, I. H. M. van Stokkum, M.-L. Groot, J. T. M. Kennis, R. van Grondelle and H. van Amerongen, Chem. Phys. Lett., 2003, 371, 157-163), exhibiting both a fluorescent and a non-fluorescent excited state. There was no evidence for significant amounts of charge-separated states in the transient-absorption spectra. The probability that an excitation of 2AP leads to stable charge transfer products was estimated to be very low (∼0.1%). In the systems we studied, the observed fluorescence quenching can largely be explained by a shift of the equilibrium between the two excited states in 2AP, in which the non-fluorescent state is favored.
AB - Ultrafast transient-absorption and steady-state fluorescence measurements have been performed on dinucleotides comprising the fluorescent adenine analogue 2-aminopurine and guanine, adenine, cytosine, thymine or hypoxanthine, respectively. Two oligodeoxyribonucleotide duplexes that were site-selectively substituted with a single 2-aminopurine moiety were also studied. A strong quenching of the steady-state fluorescence was observed in all samples. The transient-absorption spectra were remarkably similar to those of the isolated 2-aminopurine (Larsen et al.; O. F. A. Larsen, I. H. M. van Stokkum, M.-L. Groot, J. T. M. Kennis, R. van Grondelle and H. van Amerongen, Chem. Phys. Lett., 2003, 371, 157-163), exhibiting both a fluorescent and a non-fluorescent excited state. There was no evidence for significant amounts of charge-separated states in the transient-absorption spectra. The probability that an excitation of 2AP leads to stable charge transfer products was estimated to be very low (∼0.1%). In the systems we studied, the observed fluorescence quenching can largely be explained by a shift of the equilibrium between the two excited states in 2AP, in which the non-fluorescent state is favored.
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U2 - 10.1039/b308992d
DO - 10.1039/b308992d
M3 - Article
AN - SCOPUS:1642533609
SN - 1463-9076
VL - 6
SP - 154
EP - 160
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
IS - 1
ER -