Impact of Sodium Cationization on Gas-Phase Conformations of DNA and RNA Cytidine Mononucleotides
Impact of Sodium Cationization on Gas-Phase Conformations of DNA and RNA Cytidine Mononucleotides
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DOI：
10.1007/s13361-019-02274-8
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发表时间：
2019-09-01
影响因子：
3.2
通讯作者：
Rodgers, M. T.
中科院分区：
文献类型：
--
作者：
Hamlow, L. A.;Nei, Y. -w.;Rodgers, M. T.
用红外多光子解离作用光谱法研究了2 '-脱氧胞苷和胞苷单核苷酸的钠阳离子化形式[pdCyd+Na]（+）和[pCyd+Na]（+）的气相构象。在B3 LYP/6-311+G（2d，2 p）//B3 LYP/6-311+G（d，p）水平上的互补电子结构计算提供了候选构象及其各自的预测IR光谱，用于在IR指纹和氢伸缩区域之间进行比较。预测的红外光谱和测量的红外多光子解离作用光谱的比较提供了洞察钠阳离子化对内在的monocytide结构的影响。此外，本结果与那些报道的钠阳离子化胞苷核苷类似物的比较阐明了磷酸基团对气相结构的影响。在整个中性，质子化，和钠阳离子化的胞苷monocytides，磷酸部分和核碱基方向的稳定化的偏好被观察到，虽然这种稳定化的细节与阳离子化的状态不同。实验上观察到[pdCyd+Na]（+）和[pCyd+Na]（+）的几种低能构象，涉及磷酸基团的几种不同取向和糖折叠模式。
Gas-phase conformations of the sodium-cationized forms of the 2 '-deoxycytidine and cytidine mononucleotides, [pdCyd+Na](+) and [pCyd+Na](+), are examined by infrared multiple photon dissociation action spectroscopy. Complimentary electronic structure calculations at the B3LYP/6-311+G(2d,2p)//B3LYP/6-311+G(d,p) level of theory provide candidate conformations and their respective predicted IR spectra for comparison across the IR fingerprint and hydrogen-stretching regions. Comparisons of the predicted IR spectra and the measured infrared multiple photon dissociation action spectra provide insight into the impact of sodium cationization on intrinsic mononucleotide structure. Further, comparison of present results with those reported for the sodium-cationized cytidine nucleoside analogues elucidates the impact of the phosphate moiety on gas-phase structure. Across the neutral, protonated, and sodium-cationized cytidine mononucleotides, a preference for stabilization of the phosphate moiety and nucleobase orientation is observed, although the details of this stabilization differ with the state of cationization. Several low-energy conformations of [pdCyd+Na](+) and [pCyd+Na](+) involving several different orientations of the phosphate moiety and sugar puckering modes are observed experimentally.