Peyret N, Seneviratne P A, Allawi H T, SantaLucia J
Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA.
Biochemistry. 1999 Mar 23;38(12):3468-77. doi: 10.1021/bi9825091.
Thermodynamic measurements are reported for 51 DNA duplexes with A.A, C.C, G.G, and T.T single mismatches in all possible Watson-Crick contexts. These measurements were used to test the applicability of the nearest-neighbor model and to calculate the 16 unique nearest-neighbor parameters for the 4 single like with like base mismatches next to a Watson-Crick pair. The observed trend in stabilities of mismatches at 37 degrees C is G.G > T.T approximately A.A > C.C. The observed stability trend for the closing Watson-Crick pair on the 5' side of the mismatch is G.C >/= C.G >/= A.T >/= T.A. The mismatch contribution to duplex stability ranges from -2.22 kcal/mol for GGC.GGC to +2.66 kcal/mol for ACT.ACT. The mismatch nearest-neighbor parameters predict the measured thermodynamics with average deviations of DeltaG degrees 37 = 3.3%, DeltaH degrees = 7. 4%, DeltaS degrees = 8.1%, and TM = 1.1 degrees C. The imino proton region of 1-D NMR spectra shows that G.G and T.T mismatches form hydrogen-bonded structures that vary depending on the Watson-Crick context. The data reported here combined with our previous work provide for the first time a complete set of thermodynamic parameters for molecular recognition of DNA by DNA with or without single internal mismatches. The results are useful for primer design and understanding the mechanism of triplet repeat diseases.
报告了在所有可能的沃森-克里克配对环境下，51个具有A.A、C.C、G.G和T.T单碱基错配的DNA双链体的热力学测量结果。这些测量用于测试最近邻模型的适用性，并计算4种同碱基错配紧邻沃森-克里克碱基对时的16个独特的最近邻参数。在37℃观察到的错配稳定性趋势为G.G＞T.T≈A.A＞C.C。在错配5'侧的封闭沃森-克里克碱基对的观察到的稳定性趋势为G.C≥C.G≥A.T≥T.A。错配对双链体稳定性的贡献范围从GGC.GGC的-2.22千卡/摩尔到ACT.ACT的+2.66千卡/摩尔。错配最近邻参数预测测量的热力学，平均偏差为ΔG°37 = 3.3%，ΔH° = 7.4%，ΔS° = 8.1%，熔解温度（TM） = 1.1℃。一维核磁共振谱的亚氨基质子区域表明，G.G和T.T错配形成了取决于沃森-克里克配对环境的氢键结构。这里报告的数据与我们之前的工作相结合，首次提供了一套完整的热力学参数，用于有或无单内部错配的DNA对DNA分子识别。这些结果对于引物设计和理解三联体重复疾病的机制很有用。
