LeBlanc D A, Morden K M
Department of Biochemistry, Louisiana State University, Baton Rouge 70803.
Biochemistry. 1991 Apr 23;30(16):4042-7. doi: 10.1021/bi00230a031.
Ultraviolet absorption techniques were used to study the thermodynamics of duplex formation for a DNA decamer, d(GCGAAAAGCG).d(CGCTTTTCGC), and a series of related duplexes, each of which contains a bulged base centered in the A.T tract. Thermodynamic parameters were obtained from nonlinear least-squares fits of the melting curves and the concentration dependences of the melting temperatures. Duplexes containing a localized single-base bulge were found to be 3.5-4.6 kcal/mol less stable than the decamer at 37 degrees C. These results indicate that both the identity of the bulged base and the strand in which it is located may influence the amount by which the duplex is destabilized. Bulged bases located in the T-strand, d(CGCTTYTTCGC), in position Y, were observed to be slightly more destabilizing than those located in the A-strand, d(GCGAAXAAGCG), in position X. Bulged purines may be more destabilizing than bulged pyrimidines.
采用紫外吸收技术研究了DNA十聚体d(GCGAAAAGCG).d(CGCTTTTCGC)及一系列相关双链体形成双链的热力学性质，每个双链体在A·T序列中心都含有一个凸起碱基。通过对熔解曲线和熔解温度的浓度依赖性进行非线性最小二乘拟合获得热力学参数。发现在37℃时，含有局部单碱基凸起的双链体比十聚体稳定性低3.5 - 4.6千卡/摩尔。这些结果表明，凸起碱基的身份及其所在的链都可能影响双链体去稳定化的程度。观察到位于T链d(CGCTTYTTCGC)中Y位置的凸起碱基比位于A链d(GCGAAXAAGCG)中X位置的凸起碱基去稳定化作用稍强。凸起的嘌呤可能比凸起的嘧啶更具去稳定化作用。
