Triple-Helix and Double-Helix Formations of Octamers of Deoxyriboadenylic and Deoxyribothymidylic Acids

Abstract Triple-helix and double-helix formations of octamers of deoxyriboadenylic and deoxyribothymidylic acids (dA8 and dT8) have been studied spectrophotometrically. The free-energy changes in 50 mmol dm−3 MgCl2 buffer at 25 °C were −21.2 kJ mol−1 for the triplex formation and −29.3 kJ mol−1 for the duplex formation, respectively. The other results by UV and CD spectroscopies were also reported.