Structure and stability of X.G.C mismatches in the third strand of intramolecular triplexes.
Structure and stability of X.G.C mismatches in the third strand of intramolecular triplexes.
复制标题
分子内三链体第三链 X.G.C 错配的结构和稳定性。
DOI：
10.1126/science.254.5029.270
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Feigon,J
中科院分区：
文献类型：
--
作者：
Macaya,RF;Gilbert,DE;Malek,S;Sinsheimer,JS;Feigon,J
分子内DNA三联体包含由单链DNA折叠形成的8个碱基三联体，在酸性pH下容忍第三链中的单个X.G.C错配。用一维和二维质子核磁共振技术确定了可能涉及G.C.Watson-Crick碱基对的所有四个三联体的结构和相对稳定性。含有A.G.C、G.G.C或T.G.C三联体的三联体比含有C.G.C三联体的相应母体分子更不稳定。然而，所有不匹配的碱基都在双螺旋的主槽中形成了特定的氢键。这些错配对三联体稳定性的相对影响不同于(在不同条件下)用二维凝胶电泳法和用寡核苷酸EDTA、Fe(II)切割DNA所测得的影响。
Intramolecular DNA triplexes that contain eight base triplets formed from the folding of a single DNA strand tolerate a single X.G.C mismatch in the third strand at acidic pH. The structure and relative stability of all four triplets that are possible involving a G.C Watson-Crick base pair were determined with one- and two-dimensional proton nuclear magnetic resonance techniques. Triplexes containing A.G.C, G.G.C, or T.G.C triplets were less stable than the corresponding parent molecule containing a C.G.C triplet. However, all mismatched bases formed specific hydrogen bonds in the major groove of the double helix. The relative effect of these mismatches on the stability of the triplex differs from the effect assayed (under different conditions) by two-dimensional gel electrophoresis and DNA cleavage with oligonucleotide EDTA.Fe(II).