HARMONIC VIBRATIONS AND THERMODYNAMIC STABILITY OF A DNA OLIGOMER IN MONO-VALENT SALT SOLUTION
HARMONIC VIBRATIONS AND THERMODYNAMIC STABILITY OF A DNA OLIGOMER IN MONO-VALENT SALT SOLUTION
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DOI：
10.1073/pnas.86.9.3160
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发表时间：
1989-05-01
影响因子：
11.1
通讯作者：
SOUMPASIS, DM
中科院分区：
文献类型：
--
作者：
GARCIA, AE;SOUMPASIS, DM
我们计算了DNA低聚物d（C-G）3在各种离子环境（0.01-5.0 M NaCl）中优化的B和Z构象的全谐振动光谱和本征模。溶液中DNA与其周围弥散离子云的统计相互作用近似地表示在平均力框架的潜力。发现B构象的最低本征频率随着NaCl浓度的增加而急剧降低。这表明软模机制可能是B-Z转换的前兆。控制d（C-G）3的B-Z异构化的自由能平衡由溶剂平均的有效磷酸盐-磷酸盐相互作用主导，这是由于大得多的分子内能量贡献之间的实质性抵消。
We compute the full harmonic vibrational spectrum and eigenmodes of a DNA oligomer, d(C-G)3, in optimized B and Z conformations in various ionic environments (0.01-5.0 M NaCl). The statistical interactions of DNA with the diffuse ionic cloud surrounding it in solution are approximately represented within the potential of mean force framework. The lowest eigenfrequency of the B conformation is found to drastically decrease with increased NaCl concentration. This suggests that a soft mode mechanism may be a precursor for the B-to-Z conversion. The free energy balance governing the B-Z isomerization of d(C-G)3 is dominated by the solvent-averaged effective phosphate-phosphate interactions due to substantial cancelations between the much larger intramolecular energy contributions.