Faculty of Engineering and Natural Sciences, Sabancı University, Orhanlı-Tuzla, 34956 Istanbul, Turkey.
Phys Chem Chem Phys. 2011 Jul 28;13(28):12785-97. doi: 10.1039/c1cp20430k. Epub 2011 Jun 20.
An efficient method for simulating continuous-wave electron spin resonance spectra (ESR) of molecules labeled with two dipolar-coupled nitroxides from trajectories of the molecular motion is presented. Two approximate treatments of the dipolar spin evolution, resulting in significantly shorter simulation times, are examined in order to determine their range of applicability. The approach is illustrated in the context of a double-helical B-DNA. ESR spectra for DNA undergoing anisotropic global diffusion and internal stretching dynamics are calculated for three different labeling geometries with the spin labels bracketing, respectively, three, two and one base pairs. While multifrequency spectra of all three labeling schemes are very sensitive to DNA tumbling, the last one is found to be most informative about the local DNA dynamics.
本文提出了一种从分子运动轨迹模拟双偶极耦合的氮氧自由基标记分子的连续波电子自旋共振（ESR）谱的有效方法。为了确定其适用范围，研究了两种导致模拟时间显著缩短的偶极自旋演化的近似处理方法。该方法在双螺旋 B-DNA 的背景下进行了说明。对于自旋标记分别跨越三个、两个和一个碱基对的三种不同标记几何结构，计算了经历各向异性整体扩散和内部拉伸动力学的 DNA 的 ESR 谱。虽然所有三种标记方案的多频谱都对 DNA 翻滚非常敏感，但最后一种方案被发现对局部 DNA 动力学最有信息。
