钠离子对poly(dT)·poly(dA)·poly(dT)三螺旋DNA分子呼吸模式的影响

EFFECTS OF Na^+ IONS ON BREATHING VIBRATIONAL MODES OF POLY(dT)·POLY(dA)·POLY(dT)

利用分子结构的螺旋对称性 ,建立了一个包括钠离子的三链 DNA分子 poly(d T)· poly(d A)· poly(d T)的晶格动力学模型 ,计算了 poly(d T)· poly(d A)· poly(d T)的氢键呼吸模式。结果发现钠离子的加入明显地淬灭了位于较低频率的几个最为强烈的 Hoogensteen氢键呼吸模式 ,而对 Watson- Crick氢键呼吸模式影响不明显 ,这说明钠离子能提高 poly(d T)· poly(d A)· poly(d T)三螺旋结构的稳定性 .该计算结果很好地解释了 poly(d T)· poly(d A)· poly(d T)

A lattice dynamics model for poly(dT)·poly(dA)·poly(dT), which is one of the best important triplex DNA was presented based on its screw symmetry. In this model, the presence of Na + ions was included explicitly. The breathing modes of poly(dT)·poly(dA)·poly(dT) were calculated. By comparing the isolated triplex vibrational modes, it was found that the addition of Na + ions could extinguish very strong breathing modes of Hoogensteen hydrogen bond located in 18.4cm 1?36.4cm 1 and 43.8cm 1. The breathing modes of Watson Crick hydrogen bond were not changed obviously. These results indicate that Na + ions can increase the stability of poly(dT)·poly(dA)·poly(dT) and reasonably explain the melting experiment of poly(dT)·poly(dA)·poly(dT).