Ring‐current effects in the nmr of nucleic acids: A graphical approach
Ring‐current effects in the nmr of nucleic acids: A graphical approach
复制标题
核酸核磁共振中的环流效应：图形方法
作者：
C. Giessner;B. Pullman;P. Borer;L. Kan;P. Ts'o
核酸碱基环流磁各向异性的空间依赖性以一系列柱坐标图的形式呈现。这些曲线可用于计算半径为 10Å 的圆柱体中一点处的环电流位移，该圆柱体在底座的每个环上方和下方延伸 8 Å。研究发现，这些距离效应会显着影响核酸质子的预测化学位移，特别是在 RNA 双链体中。简要讨论了极化（电场）效应和单个原子的抗磁各向异性（局部 Δχ）的贡献。
The spatial dependence of the ring‐current magnetic anisotropy of nucleic acid bases is presented in a series of graphs in cylindrical coordinates. The curves may be used to calculate the ring‐current shift at a point in a cylinder of radius 10Å extending 8 Å above and below each ring of the base. These distance effects are found to influence considerably the predicted chemical shifts of nucleic acid protons, particularly in RNA duplexes. The contribution of polarization (electric field) effects and the diamagnetic anisotropy of individual atoms (local Δχ) are briefly discussed.