Sychrovský Vladimír, Vokácová Zuzana, Sponer Jirí, Spacková Nad'a, Schneider Bohdan
Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
J Phys Chem B. 2006 Nov 16;110(45):22894-902. doi: 10.1021/jp065000l.
Calculated indirect NMR spin-spin coupling constants (J-couplings) between (31)P, (13)C, and (1)H nuclei were related to the backbone torsion angles of nucleic acids (NAs), and it was shown that J-couplings can facilitate accurate and reliable structural interpretation of NMR measurements and help to discriminate between their distinct conformational classes. A proposed stepwise procedure suggests assignment of the J-couplings to torsion angles from the sugar part to the phosphodiester link. Some J-couplings show multidimensional dependence on torsion angles, the most prominent of which is the effect of the sugar pucker. J-couplings were calculated in 16 distinct nucleic acid conformations, two principal double-helical DNAs, B- and A-, the main RNA form, A-RNA, as well as in 13 other RNA conformations. High-level quantum mechanics calculations used a baseless dinucleoside phosphate as a molecular model, and the effect of solvent was included. The predicted J-couplings correlate reliably with available experimental data from the literature.
计算得到的（³¹）P、（¹³）C和（¹）H原子核之间的间接核磁共振自旋-自旋耦合常数（J耦合）与核酸（NA）的主链扭转角相关，结果表明J耦合有助于对核磁共振测量进行准确可靠的结构解释，并有助于区分不同的构象类别。提出的逐步程序建议将J耦合从糖部分到磷酸二酯键的扭转角进行赋值。一些J耦合显示出对扭转角的多维依赖性，其中最显著的是糖环构象的影响。在16种不同的核酸构象中计算了J耦合，包括两种主要的双螺旋DNA，B型和A型，主要的RNA形式A-RNA，以及其他13种RNA构象。高水平的量子力学计算使用无碱基磷酸二核苷作为分子模型，并考虑了溶剂的影响。预测的J耦合与文献中可用的实验数据可靠相关。
