Brown T, Leonard G A, Booth E D, Kneale G
Department of Chemistry, University of Edinburgh, U.K.
J Mol Biol. 1990 Apr 5;212(3):437-40. doi: 10.1016/0022-2836(90)90320-L.
A series of self-complementary dodecanucleotide duplexes containing two symmetrically disposed mismatches have been studied by pH-dependent, ultraviolet light melting techniques. The results indicate that A.C, and C.C mismatches are strongly stabilized by protonation and that the degree of stabilization of the A.C mismatch depends greatly on the flanking bases. In one case, a duplex containing two A.C mismatches is more stable than the native sequence below pH 5.5. The G.A mismatch displays conformational flexibility, with a protonated G(syn).A(anti) base-pair occurring in certain base stacking environments but not in others. The A.A and T.C mismatches are not stabilized at low pH. These solution studies correlate well with predictions based on X-ray crystallographic data.
通过pH依赖性紫外光熔解技术研究了一系列含有两个对称分布错配的自互补十二聚体双链体。结果表明，A·C和C·C错配通过质子化得到强烈稳定，并且A·C错配的稳定程度在很大程度上取决于侧翼碱基。在一种情况下，含有两个A·C错配的双链体在pH 5.5以下比天然序列更稳定。G·A错配表现出构象灵活性，质子化的G（顺式）·A（反式）碱基对在某些碱基堆积环境中出现，但在其他环境中不出现。A·A和T·C错配在低pH下不稳定。这些溶液研究与基于X射线晶体学数据的预测很好地相关。
