Jp. Barnes et Wa. Bernhard, THE DISTRIBUTION OF ELECTRON TRAPPING IN DNA - ONE-ELECTRON-REDUCED OLIGODEOXYNUCLEOTIDES OF ADENINE AND THYMINE, Radiation research, 143(1), 1995, pp. 85-92
A series of single- and double-stranded oligodeoxynucleotides of adeni
ne and thymine, 8 to 12 nucleotides in length, were one-electron-reduc
ed at 10 K in a >8 M LiCl/H2O glass. The Q-band electron paramagnetic
resonance (EPR) spectra of these radicals show that thymine is the dom
inant trapping site for mobile electrons in these oligomers. The spect
ra of the reduced oligomers in the series pd(A(n)T(10-n)). pd(A(10-n)T
(n)) with n = 5-->10 showed a trend which is interpreted as either an
increase in the probability of trapping at an adenine base in tracks o
f adenine >7 base pairs in length, or the presence of different proton
ated states of the one-electron-reduced bases due to the adoption of a
different conformational state for longer tracks of adenine, or a com
bination of these two possibilities. Analysis of the trends in the EPR
spectra of the radicals as a function of sequence using multicomponen
t analysis is presented. (C) 1995 by Radiation Research Society