波谱学杂志2016，Vol.33Issue(3)：378-394,17.DOI:10.11938/cjmr20160303
分子间相互作用对核酸碱基中17O屏蔽张量与四极耦合常数影响的理论计算研究
Influences of Intermolecular Interactions on the17O Nuclear Magnetic Parameters in Nucleic Acid Bases：A Theoretical Investigation
摘要
Abstract
The influence of hydrogen bonding on the shielding tensors and quadrupole coupling constant (QCC) of oxygen atoms in [17O-2] thymine, [17O-4] thymine, [17O-2] uracil, [17O-4] uracil, [17O-2] cytosine, and [17O-6] guanine monohydrate has been studied by high quality quantum chemical calculations with different cluster models. The results showed that both hydrogen bonding and van der Waals (vdW) interactions are crucial for accurate prediction of isotropic17O chemical shifts (dO). In addition, experimentally measured17O chemical shifts in these bases decrease with the increase of intermolecular hydrogen bonding interactions, and such interactions need to be accounted for in the theoretical models in order to obtain satisfactory calculated results. Relative to that ofdO, the calculation of17O shielding tensors (d11,d22andd33) are even more model-dependent. NMR parameters calculated by periodic structure models taking all hydrogen bonding interactions and non-bonding vdW interactions into account were found to be in good agreement with the experimental results. Further analysis revealed that intermolecular hydrogen bonding-induced decrease ofdO is mainly due to the increaseof17O negative charge density coming from the carboxyl (C=O) carbon. Furthermore, it was found that hydrogen bonding and weak interaction have remarkable effects on calculated17O quadrupole coupling constant (QCC)as well. In conclusion, it is essential to take intermolecular hydrogen bonding and weak interactions into accounts in theoretical calculations in order to predict NMR parameters of biological samples correctly.关键词
核磁共振(NMR)/屏蔽张量/量子化学计算/核酸碱基/四极耦合常数Key words
NMR/shielding tensor/quantum chemical calculation/nucleic acid bases/quadrupole coupling constant分类
数理科学引用本文复制引用
宋本腾,褚月英,王吉清,郑安民,邓风..分子间相互作用对核酸碱基中17O屏蔽张量与四极耦合常数影响的理论计算研究[J].波谱学杂志,2016,33(3):378-394,17.基金项目
国家自然科学基金资助项目(21522310,21173255)，湖南省教育厅重点资助项目(14A040) （21522310,21173255）
