Notable effect of water on excess electron attachment to aqueous DNA deoxyribonucleosides
Notable effect of water on excess electron attachment to aqueous DNA deoxyribonucleosides
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水对水性 DNA 脱氧核糖核苷的过量电子附着有显着影响
DOI：
10.1039/c9cp00536f
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发表时间：
2019
影响因子：
3.3
通讯作者：
Songqiu Yang
中科院分区：
文献类型：
--
作者：
Yan Zhang;Jiayue Wang;Songqiu Yang
采用量子力学/分子力学（QM/MM）方法研究了脱氧核糖核苷（dRNs）水溶液中过量电子的吸附和分离.四个dRN的QM/MM垂直电子亲和势（VEAs）比相应的核碱基的值高出约0.20 eV。QM/MM非绝热电子亲合能（AEAs）比隐式溶剂模型的计算值大得多。体水引起明显的VEA和AEA增加，使垂直脱离能增加1.20 eV以上。它影响过量的电子附着和脱离水性dRN和稳定的阴离子。此外，脱氧腺苷（dA）阴离子周围的水分子与dA形成分子间氢键，并打破了在气体结构中发现的dA的分子内氢键。在垂直电子附着中，超过50%的多余电子将在dRN周围的水分子上离域。阴离子结构弛豫导致多余的电子从水分子转移到dRN核碱基。然而，主要的过剩电子（ε-0.76 e）将位于稳定的阴离子结构中的dRN核碱基上。
Computations using the combined quantum mechanical/molecular mechanical (QM/MM) method were performed to investigate excess electron attachment to and detachment from aqueous deoxyribonucleosides (dRNs). The QM/MM vertical electron affinities (VEAs) of four dRNs are higher than the values of the corresponding nucleobases by ∼0.20 eV. The QM/MM diabatic electron affinities (AEAs) are much larger than the calculations of the implicit solvent model. Bulk water induces evident VEA and AEA increases and boosts the vertical detachment energies by over 1.20 eV. It affects excess electron attachment to and detachment from aqueous dRNs and stabilizes the anions. Moreover, the water molecules around deoxyadenosine (dA) anions form intermolecular hydrogen bonds with dA and break the intramolecular hydrogen bond of dA which had been found in the gas structure. In vertical electron attachment, ∼50% of excess electrons would be delocalized over the water molecules around the dRNs. The anionic structural relaxations cause the transfer of ∼−0.30 e excess electrons from the water molecules to the dRN nucleobases. However, the main excess electrons (∼−0.76 e) would be localized on dRN nucleobases in the stable anionic structure.