Measurement of long-range 1H-19F scalar coupling constants and their glycosidic torsion dependence in 5-fluoropyrimidine-substituted RNA
Measurement of long-range 1H-19F scalar coupling constants and their glycosidic torsion dependence in 5-fluoropyrimidine-substituted RNA
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DOI：
10.1021/ja060165t
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发表时间：
2006-05-03
影响因子：
15
通讯作者：
Williamson, JR
中科院分区：
文献类型：
--
作者：
Hennig, M;Munzarova, ML;Williamson, JR
在5-氟嘧啶取代的RNA中观察到远距离标量(5)J（H1’，F）偶联。我们开发了一种新的(SE)- e -3-F-19 α， β编辑的NOESY实验，用于定量这些远程标量(5)J（H1‘，F）耦合，其中J耦合可以通过检查残差（H1’，H6） NOE交叉峰来提取。利用量子化学计算来研究寡核苷酸中糖苷键周围的标量耦合和构象之间的关系。观测到的(5)J（H1'，F）耦合与扭转角chi的理论依赖关系可以用广义Karplus关系来描述。给出了相应的密度泛函理论（DFT）分析。进一步的核磁共振实验促进了5-氟嘧啶取代的rna的共振分配，并提出了由于氟-19 （F-19）存在下屏蔽改变而引起的化学位移变化。
Long-range scalar (5)J(H1',F) couplings were observed in 5-fluoropyrimidine-substituted RNA. We developed a novel (SE)-E-3-F-19-alpha,beta-edited NOESY experiment for quantitation of these long-range scalar (5)J(H1',F) couplings, where the J-couplings can be extracted from inspection of intraresidual (H1',H6) NOE cross-peaks. Quantum chemical calculations were exploited to investigate the relation between scalar couplings and conformations around the glycosidic bond in oligonucleotides. The theoretical dependence of the observed (5)J(H1',F) couplings on the torsion angle chi can be described by a generalized Karplus relationship. The corresponding density functional theory (DFT) analysis is outlined. Additional NMR experiments facilitating the resonance assignments of 5-fluoropyrimidine-substituted RNAs are described, and chemical shift changes due to altered shielding in the presence of fluorine-19 (F-19) are presented.