Wu M, SantaLucia J, Turner D H
Department of Chemistry, University of Rochester, New York 14627-0216, USA.
Biochemistry. 1997 Apr 15;36(15):4449-60. doi: 10.1021/bi9625915.
The three-dimensional solution structure of the RNA self-complementary duplex [formula in text] was derived from two-dimensional NMR and the iterative relaxation matrix approach. Each GA mismatch forms two hydrogen bonds: A-NH6 to G-O6 and A-N1 to G-NH1 (imino). This GA structure differs from the sheared tandem GA structure in [formula in text] which also has two hydrogen bonds: A-N7 to G-NH2 and A-NH6 to G-N3 [SantaLucia, J., Jr & Turner, D. H. (1993) Biochemistry 32, 12612-12623], although the only difference between the two sequences is the order of the two GA mismatches. Inspection of three-dimensional structures indicates that substituting [formula in text] for [formula in text] makes GA mismatches unable to have stable sheared conformations. This may explain why the [formula in text] motif is rarely observed in nature, whereas [formula in text] common.
RNA 自互补双链体[文中公式]的三维溶液结构是通过二维核磁共振和迭代弛豫矩阵方法推导出来的。每个 GA 错配形成两个氢键：A 的 NH6 与 G 的 O6 以及 A 的 N1 与 G 的 NH1（亚氨基）。这种 GA 结构与[文中公式]中的剪切串联 GA 结构不同，后者也有两个氢键：A 的 N7 与 G 的 NH2 以及 A 的 NH6 与 G 的 N3[圣卢西亚，J.，Jr 和特纳，D. H.（1993 年）《生物化学》32，12612 - 12623]，尽管这两个序列之间的唯一区别是两个 GA 错配的顺序。对三维结构的检查表明，用[文中公式]替换[文中公式]会使 GA 错配无法具有稳定的剪切构象。这可能解释了为什么[文中公式]基序在自然界中很少被观察到，而[文中公式]却很常见。
