Effect of γ-hydroxypropano deoxyguanosine, the major acrolein-derived adduct, on monomolecular quadruplex structure of telomeric repeat d(TTAGGG)4

The three oligodeoxyribonucleotides (ODNs) a–c, having the telomeric repeat d(TTAGGG)4 sequence and incorporating γ-hydroxypropano deoxyguanosine at different positions, were synthesized. Gel electrophoresis and CD analyses indicated that the ODNs assume monomolecular quadruplex structures in Na+ and in K+ buffers. The Tm values, obtained by CD melting experiments, showed that the presence of the acrolein-dG adduct into the ODN b decreases the thermal stability of the monomolecular quadruplex structure in Na+ solution, whereas for a and c no significant effect could be detected in the same experimental conditions. On the contrary, all ODNs a–d show the same behaviour in K+ buffer. These findings are briefly discussed.