Kypr J, Vorlícková M
Biochem Biophys Res Commun. 1984 Sep 17;123(2):831-5. doi: 10.1016/0006-291x(84)90305-x.
Thermal melting of a synthetic DNA poly(dA-dT).poly(dA-dT) was investigated in methanol-water solutions. Methanol decreased melting temperature of the polynucleotide but the decrease was qualitatively different in the presence of milimolar concentrations of sodium and cesium cations. The difference is a consequence of the fact that poly(dA-dT).poly(dA-dT) undergoes a helix-helix conformational isomerization in methanol-water solutions which is cesium cation specific. The arising conformation is much more stable than the conformation which poly(dA-dT).poly(dA-dT) adopts in solutions with sodium cations at high methanol concentrations. The (A+T) rich DNA of Bacillus cereus displays a similar behaviour.
在甲醇 - 水溶液中研究了合成DNA聚（dA - dT）·聚（dA - dT）的热解链。甲醇降低了多核苷酸的解链温度，但在毫摩尔浓度的钠和铯阳离子存在下，这种降低在性质上有所不同。这种差异是由于聚（dA - dT）·聚（dA - dT）在甲醇 - 水溶液中经历了一种铯阳离子特异性的螺旋 - 螺旋构象异构化这一事实导致的。所产生的构象比聚（dA - dT）·聚（dA - dT）在高甲醇浓度下含钠阳离子的溶液中所采用的构象更稳定。蜡样芽孢杆菌富含（A + T）的DNA表现出类似的行为。
