Thermodynamics and NMR of internal GT mismatches in DNA
Thermodynamics and NMR of internal GT mismatches in DNA
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DOI：
10.1021/bi962590c
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发表时间：
1997-08-26
期刊：
影响因子：
2.9
通讯作者：
SantaLucia, J
中科院分区：
文献类型：
--
作者：
Allawi, HT;SantaLucia, J
根据 UV 吸光度与温度曲线确定溶解在 1M NaCl 中的 39 种具有内部 G.T 错配的寡核苷酸的热力学。这些数据与六个序列的文献值相结合，得出 10 个具有 G.T 错配和 Watson-Crick 碱基对的线性独立三聚体和四聚体序列的参数。 G.T 失配参数预测 Delta G(37)(0)、Delta H-0、Delta S-0 和 T-M 的平均偏差分别为 5.1%、7.5%、8.0% 和 1.4 摄氏度。这些预测在最近邻模型的预期范围内。数据显示，单个 G.T 错配对螺旋稳定性的贡献取决于上下文，范围从 AGA/TTT 的 +1.05 kcal/mol 到 CGC/GTG 的 -1.05 kcal/mol。描述了最近邻模型对 G.T 不匹配的适用性的几个测试。亚氨基质子化学位移分析表明，G.T 错配引起的结构扰动是高度局部化的。一维 NOE 差异谱表明 G.T 错配在不同的环境中形成稳定的氢键摆动对。还提出了 Watson-Crick 碱基对的精炼最近邻参数。
Thermodynamics of 39 oligonucleotides with internal G.T mismatches dissolved in I M NaCl were determined from UV absorbance versus temperature profiles. These data were combined with literature values of six sequences to derive parameters for 10 linearly independent trimer and tetramer sequences with G.T mismatches and Watson-Crick base pairs. The G.T mismatch parameters predict Delta G(37)(0), Delta H-0, Delta S-0, and T-M with average deviations of 5.1%, 7.5%, 8.0%, and 1.4 degrees C, respectively. These predictions an within the limits of what can be expected for a nearest-neighbor model. The data show that the contribution of a single G. T mismatch to helix stability is context dependent and ranges from +1.05 kcal/mol for AGA/TTT to -1.05 kcal/mol for CGC/GTG. Several tests of the applicability of the nearest-neighbor model to G.T mismatches are described. Analysis of imino proton chemical shifts show that structural perturbations from the G.T mismatches are highly localized. One-dimensional NOE difference spectra demonstrate that G.T mismatches form stable hydrogen-bonded wobble pairs in diverse contexts. Refined nearest-neighbor parameters for Watson-Crick base pairs are also presented.