Dynamics of the excited-state hydrogen transfer in a (dG)·(dC) homopolymer: intrinsic photostability of DNA.
Dynamics of the excited-state hydrogen transfer in a (dG)·(dC) homopolymer: intrinsic photostability of DNA.
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DOI：
10.1039/c8sc03252a
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发表时间：
2018-11-07
期刊：
影响因子：
8.4
通讯作者：
Monari A
中科院分区：
文献类型：
--
作者：
Francés-Monerris A;Gattuso H;Roca-Sanjuán D;Tuñón I;Marazzi M;Dumont E;Monari A
多尺度分子动力学模拟揭示了有利于DNA光稳定性的平面外扭曲。一种新的光稳定性机制，涉及四个质子转移和附近的Na+离子触发也被揭开。核酸的内在光稳定性与生命的进化密切相关，而在分子和电子水平上对其的理解仍然是现代科学的挑战。在过去二十年中提出的不同衰变途径中，鸟嘌呤-胞嘧啶碱基对之间的激发态氢转移已被确定为有效的非反应性通道，以耗散由光吸收提供的过量能量。本工作研究了这种现象发生在（dG）（dC）B-DNA均聚物在水溶液中的动力学，使用国家的最先进的分子建模和模拟方法。一个动态的效果，提高链间的氢原子转移，固有的沃森-克里克碱基配对的光稳定性，被揭开，并归因于质子转移步骤过程中释放的能量。我们的结果还揭示了一种新的DNA衰变机制，称为四质子转移（FPT），其中两个相邻的G-C碱基对的两个质子转移，形成一个双自由基两性离子中间体。后一个中间体衰变到基态触发质子转移回到鸟嘌呤分子，恢复四聚体的沃森-克里克结构。该FPT过程通过附近的Na+抗衡离子与鸟嘌呤核碱基的氧原子的密切相互作用来激活，因此代表了在天然核酸中可操作的光稳定通道。
Multiscale molecular dynamics simulations reveal out-of-plane distortions that favour DNA photostability. A novel photostability mechanism involving four proton transfers and triggered by a nearby Na+ ion is also unveiled. The intrinsic photostability of nucleic acids is intimately related to evolution of life, while its understanding at the molecular and electronic levels remains a challenge for modern science. Among the different decay pathways proposed in the last two decades, the excited-state hydrogen transfer between guanine–cytosine base pairs has been identified as an efficient non-reactive channel to dissipate the excess of energy provided by light absorption. The present work studies the dynamics of such phenomena taking place in a (dG)·(dC) B-DNA homopolymer in water solution using state-of-the-art molecular modelling and simulation methods. A dynamic effect that boosts the photostability of the inter-strand hydrogen atom transfers, inherent to the Watson–Crick base pairing, is unveiled and ascribed to the energy released during the proton transfer step. Our results also reveal a novel mechanism of DNA decay named four proton transfer (FPT), in which two protons of two adjacent G–C base pairs are transferred to form a biradical zwitterionic intermediate. Decay of the latter intermediate to the ground state triggers the transfer of the protons back to the guanine molecules recovering the Watson–Crick structure of the tetramer. This FPT process is activated by the close interaction of a nearby Na+ counterion with the oxygen atoms of the guanine nucleobases and hence represents a photostable channel operative in natural nucleic acids.
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影响因子：
15
作者：
Groenhof, Gerrit;Schaefer, Lars V.;Robb, Michael A.
通讯作者：
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影响因子：
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影响因子：
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作者：
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通讯作者：
KLEIN, ML
DOI：
10.1073/pnas.1014982107
发表时间：
2010-12-14
影响因子：
11.1
作者：
Barbatti, Mario;Aquino, Adelia J. A.;Lischka, Hans
通讯作者：
Lischka, Hans