尿嘧啶缺陷对DNA结构的影响：500兆赫的1H核磁共振研究

Delort A M, Neumann J M, Molko D, Hervé M, Téoule R, Tran Dinh S

Nucleic Acids Res. 1985 May 10;13(9):3343-55. doi: 10.1093/nar/13.9.3343.

The local structure of two self complementary oligonucleotides d(GTAC-GTAC) and d(GTACGUAC) which differ only by the presence of uracil, not a normal component of DNA, have been investigated by 1H NMR at 500 MHz. The two octamers exhibit the same thermodynamical constants (t 1/2, delta H), their exchangeable protons broaden and disappear at the same temperature. The T-U substitution did not induce any significant changes on non exchangeable protons resonances from 2-D COSY and 2-D NOESY experiments. So the two octamers exhibit the same global structure. The only variation was detected by 1D NOE measurements: the base orientations around the N glycosidic bonds (chi angles) are different.

通过500兆赫的1H核磁共振研究了两种仅因尿嘧啶（而非DNA的正常成分）的存在而不同的自互补寡核苷酸d(GTAC - GTAC)和d(GTACGUAC)的局部结构。这两种八聚体表现出相同的热力学常数（半衰期t1/2，焓变ΔH），它们的可交换质子在相同温度下变宽并消失。二维化学位移相关谱（2-D COSY）和二维核欧沃豪斯效应谱（2-D NOESY）实验表明，T-U取代对不可交换质子的共振没有引起任何显著变化。因此，这两种八聚体具有相同的整体结构。通过一维核欧沃豪斯效应（1D NOE）测量仅检测到一处变化：N-糖苷键周围的碱基取向（χ角）不同。