Gas-Phase Conformations and Energetics of Protonated 2'-Deoxyguanosine and Guanosine: IRMPD Action Spectroscopy and Theoretical Studies.
Gas-Phase Conformations and Energetics of Protonated 2'-Deoxyguanosine and Guanosine: IRMPD Action Spectroscopy and Theoretical Studies.
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质子化 2-脱氧鸟苷和鸟苷的气相构象和能量学：IRMPD 作用光谱和理论研究。
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发表时间：
2014
影响因子：
3.3
通讯作者：
M. Rodgers
中科院分区：
文献类型：
--
作者：
R. Wu;Bo Yang;G. Berden;J. Oomens;M. Rodgers
用红外多光子解离作用谱(IRMPD)和理论电子结构计算研究了质子化的2‘-脱氧鸟苷[dGuo+H](+)及其RNA类似物[Guo+H](+)的气相结构。用FELIX自由电子激光器测量了从∼550到1900 cm(-1)的红外光谱，用光学参量振荡器/放大器激光系统测量了从∼2800到3800 cm(-1)的红外光谱。比较了[dGuo+H](+)和[Guo+H](+)的红外光谱，并与B3LYP/6-311+G(d，p)的线性红外光谱进行了比较，以确定质子化的最有利位置，鉴定了实验中获得的结构，并阐明了2‘-羟基取代基对结构和IRMPD光谱特征的影响。理论能量学和测量的IRMPD谱发现，N7质子化对于[dGuo+H](+)和[Guo+H](+)都是优先的，而O6和N3质子化构象的稳定性要差得多。2‘-羟基取代基对[dGuo+H](+)与[Guo+H](+)的稳定低能构象的结构和相对稳定性没有显著影响，但提供了额外的氢键机会，使[Guo+H](+)发现了更多的低能结构。[dGuo+H](+)和[Guo+H](+)在Felix区和OPO区具有非常相似的IRMPD光谱特征，而2‘-羟基取代基的影响主要体现在所测红外光谱的相对强度上。测量的OPO/OPA光谱特征主要反映了与O-H和N-H伸展相关的红外特征，提供了对Felix区域的补充信息，并使来自不同质子化位置的构象更容易区分。从这项研究以及对其他DNA和RNA核苷和核苷酸的平行研究中获得的洞察力，应该有助于更好地阐明当地环境对DNA和RNA整体结构的影响。
The gas-phase structures of protonated 2'-deoxyguanosine, [dGuo+H](+), and its RNA analogue protonated guanosine, [Guo+H](+), are investigated by infrared multiple photon dissociation (IRMPD) action spectroscopy and theoretical electronic structure calculations. IRMPD action spectra are measured over the range extending from ∼550 to 1900 cm(-1) using the FELIX free electron laser and from ∼2800 to 3800 cm(-1) using an optical parametric oscillator/amplifier (OPO/OPA) laser system. The measured IRMPD spectra of [dGuo+H](+) and [Guo+H](+) are compared to each other and to B3LYP/6-311+G(d,p) linear IR spectra predicted for the stable low-energy conformations computed for these species to determine the most favorable site of protonation, identify the structures accessed in the experiments, and elucidate the influence of the 2'-hydroxyl substituent on the structures and the IRMPD spectral features. Theoretical energetics and the measured IRMPD spectra find that N7 protonation is preferred for both [dGuo+H](+) and [Guo+H](+), whereas O6 and N3 protonated conformers are found to be much less stable. The 2'-hydroxyl substituent does not exert a significant influence on the structures and relative stabilities of the stable low-energy conformations of [dGuo+H](+) versus [Guo+H](+) but does provide additional opportunities for hydrogen bonding such that more low-energy structures are found for [Guo+H](+). [dGuo+H](+) and [Guo+H](+) share very parallel IRMPD spectral features in the FELIX and OPO regions, whereas the effect of the 2'-hydroxyl substituent is primarily seen in the relative intensities of the measured IR bands. The measured OPO/OPA spectral signatures, primarily reflecting the IR features associated with the O-H and N-H stretches, provide complementary information to that of the FELIX region and enable the conformers that arise from different protonation sites to be more readily distinguished. Insight gained from this and parallel studies of other DNA and RNA nucleosides and nucleotides should help better elucidate the effects of the local environment on the overall structures of DNA and RNA.
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作者：
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影响因子：
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