A 300- and 600-MHz proton nuclear magnetic resonance investigation of a 12 base pair deoxyribonucleic acid restriction fragment: relaxation behavior of the low-field resonances in water.
A 300- and 600-MHz proton nuclear magnetic resonance investigation of a 12 base pair deoxyribonucleic acid restriction fragment: relaxation behavior of the low-field resonances in water.
复制标题
12 碱基对脱氧核糖核酸限制性片段的 300 MHz 和 600 MHz 质子核磁共振研究：水中低场共振的弛豫行为。
DOI：
10.1021/bi00516a014
复制
发表时间：
1981
期刊：
影响因子：
2.9
通讯作者：
Wells,RD
中科院分区：
文献类型：
--
作者：
Early,TA;Kearns,DR;Hillen,W;Wells,RD
托马斯A. Early，* 大卫R. Kearns，* Wolfgang Hillen，®和Robert D.威尔斯摘要：本文给出了一个12个碱基对（bp）限制性片段的可交换亚氨基质子的高分辨率（300-和600-MHz）质子NMR谱和300-MHz弛豫数据。这些结果的分析允许的结论internalmotions在这个短的DNA螺旋的性质，负责所观察到的弛豫速率的各种相互作用的性质，和A* T碱基对的开放的机制。通过结合有关热稳定性和化学位移的信息与基本的环电流位移计算，低场光谱中的所有AT和GC共振可以被识别，并暂时分配给分子中的特定碱基对。用长脉冲方法测量了不同温度下低场共振的自旋-自旋（R2）和自旋-晶格（RJ）弛豫率。低场共振的低温弛豫行为可以用一个模型来解释，在这个模型中，分子被视为刚性转子，弛豫完全归因于质子-质子和质子-氮偶极相互作用。在21 ℃时，我们发现理论和实验之间有很好的定量一致性，
Thomas A. Early,* David R. Kearns,* Wolfgang Hillen,® and Robert D. Wells abstract: High-resolution (300-and 600-MHz) proton NMR spectra and 300-MHz relaxationdata on the ex-changeable imino protons of a 12 base pair (bp) restriction fragment are presented. Analysis of these results permits conclusions on the nature of internalmotions in this short DNA helix, the nature of the various interactions which are responsible for the observed relaxation rates, and the mechanism of opening of A* T base pairs. By combining information on the thermal stability and the chemical shifts of the reso-nances with rudimentary ring current shift calculations, all AT and GC resonances in the low-field spectrum can be identified and tentatively assigned to specific base pairs in the molecule. Spin-spin (R2) and spin-lattice (RJ relaxation rates of the low-field resonances have been measured at a number of temperatures by using the long-pulse method. The lowtemperature relaxation behavior of the low-field resonances can be accounted for theoretically in terms of a model in which the molecule is treated as a rigid rotor and in which the re-laxation is entirely attributed to proton-proton and proton-nitrogen dipolar interactions. At 21 C, we find good quan-titative agreement between theory and experiment, and various