Research output: Contribution to journal › Article › peer-review
Photophysical processes in the complexes of DNA with ethidium bromide and acridine orange : A femtosecond study. / Kononov, Alexei I.; Moroshkina, Evgeniya B.; Tkachenko, Nikolai V.; Leninietyinen, Helge.
In: Journal of Physical Chemistry B, Vol. 105, No. 2, 18.01.2001, p. 535-541.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Photophysical processes in the complexes of DNA with ethidium bromide and acridine orange
T2 - A femtosecond study
AU - Kononov, Alexei I.
AU - Moroshkina, Evgeniya B.
AU - Tkachenko, Nikolai V.
AU - Leninietyinen, Helge
N1 - Copyright: Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2001/1/18
Y1 - 2001/1/18
N2 - Ethidium bromide (EB) and acridine orange (AO) in the complexes with DNA in aqueous solution were studied using variety of spectroscopy techniques: emission up-conversion, absorption pump-probe, flashphotolysis, steady-state luminescence, and circular dichroism (CD). Combination of the methods allowed to detect oxidized form of ethidium and to associate this with a fast 10 ps component observed in the upconversion experiments. Thus, a photoinduced electron transfer from a small fraction of the dyes to the DNA bases was concluded. It suggests that those DNA sites have a redox potential higher than -0.9 V (an upper limit for the excited-state oxidation potential of ethidium), while the redox potential of the most affinic DNA bases, thymine and cytosine in water, is -1.09 V. It is proposed that certain conformations of the stacked bases have low-lying electronic orbitals. The involvement of such low-lying electronic levels in the processes of electron transfer through DNA stack is suggested. The results obtained by the pump-probe experiments for the AO-DNA system and by the CD measurements for the EB-DNA complex point at a delocalization of the electronic excitation over the neighboring dyes separated by two base pairs, i.e., 10 Å, in the DNA stack.
AB - Ethidium bromide (EB) and acridine orange (AO) in the complexes with DNA in aqueous solution were studied using variety of spectroscopy techniques: emission up-conversion, absorption pump-probe, flashphotolysis, steady-state luminescence, and circular dichroism (CD). Combination of the methods allowed to detect oxidized form of ethidium and to associate this with a fast 10 ps component observed in the upconversion experiments. Thus, a photoinduced electron transfer from a small fraction of the dyes to the DNA bases was concluded. It suggests that those DNA sites have a redox potential higher than -0.9 V (an upper limit for the excited-state oxidation potential of ethidium), while the redox potential of the most affinic DNA bases, thymine and cytosine in water, is -1.09 V. It is proposed that certain conformations of the stacked bases have low-lying electronic orbitals. The involvement of such low-lying electronic levels in the processes of electron transfer through DNA stack is suggested. The results obtained by the pump-probe experiments for the AO-DNA system and by the CD measurements for the EB-DNA complex point at a delocalization of the electronic excitation over the neighboring dyes separated by two base pairs, i.e., 10 Å, in the DNA stack.
UR - http://www.scopus.com/inward/record.url?scp=0035132308&partnerID=8YFLogxK
U2 - 10.1021/jp002615o
DO - 10.1021/jp002615o
M3 - Article
AN - SCOPUS:0035132308
VL - 105
SP - 535
EP - 541
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
SN - 1520-6106
IS - 2
ER -
ID: 76775182