溶液中聚（dA）·聚（dT）的异源DNA模型的不可行性。这种DNA采用右手B-DNA双链体，其中两条链在构象上是等效的。一项使用一维核Overhauser效应的500兆赫核磁共振研究。
Untenability of the heteronomous DNA model for poly(dA).poly(dT) in solution. This DNA adopts a right-handed B-DNA duplex in which the two strands are conformationally equivalent. A 500 MHz NMR study using one dimensional NOE.
作者信息
Sarma M H, Gupta G, Sarma R H
机构信息
Institute of Biomolecular Stereodynamics, State University of New York, Albany 12222.
出版信息
J Biomol Struct Dyn. 1985 Jun;2(6):1057-84. doi: 10.1080/07391102.1985.10507624.
1D NOE 1H NMR spectroscopy at 500 MHz was employed to examine the structure of poly(dA).poly(dT) in solution. NOE experiments were conducted as a function of presaturation pulse length (50, 30, 20 and 10 msec) and power (19 and 20 db) to distinguish the primary NOEs from spin diffusion. The 10 msec NOE experiments took 49 hrs and over 55,000 scans for each case and the difference spectra were almost free from diffusion. The spin diffused NOE difference spectra as well as difference NOE spectra in 90% H2O + 10% D2O in which TNH3 was presaturated enabled to make a complete assignment of the base and sugar protons. It is shown that poly(dA).poly(dT) melts in a fashion in which single stranded bubbles are formed with increasing temperature.
采用500兆赫的一维NOE 1H核磁共振光谱法来研究溶液中聚（dA）·聚（dT）的结构。进行了作为预饱和脉冲长度（50、30、20和10毫秒）和功率（19和20分贝）函数的NOE实验，以区分初级NOE与自旋扩散。10毫秒的NOE实验每种情况需要49小时且扫描次数超过55000次，差异光谱几乎没有扩散现象。自旋扩散的NOE差异光谱以及在TNH3被预饱和的90% H2O + 10% D2O中的差异NOE光谱能够对碱基和糖质子进行完整的归属。结果表明，聚（dA）·聚（dT）随着温度升高以形成单链气泡的方式熔化。
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