Direct observation of the oxidation of DNA bases by phosphate radicals formed under radiation: a model of the backbone-to-base hole transfer.
Direct observation of the oxidation of DNA bases by phosphate radicals formed under radiation: a model of the backbone-to-base hole transfer.
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DOI：
10.1039/c8cp00352a
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发表时间：
2018-05-30
期刊：
影响因子：
--
通讯作者：
Mostafavi M
中科院分区：
文献类型：
--
作者：
Ma J ;Marignier JL ;Pernot P ;Houée-Levin C ;Kumar A ;Sevilla MD ;Adhikary A ;Mostafavi M
在辐照的DNA中，通过碱基-碱基和主链-碱基空穴转移过程，空穴（即，未配对的自旋）定位在最正电性的碱基鸟嘌呤上。通过电离事件在DNA骨架中形成的磷酸根自由基必须在骨架到碱基的空穴转移过程中发挥重要作用。然而，早期的工作辐照水合DNA，在冷冻水溶液中的辐照DNA模型和纯磷酸二甲酯显示形成碳中心的自由基，而不是磷酸根。因此，为了模拟主链到碱基的空穴转移过程，我们报告了22 °C下6 M H3 PO 4中H2 PO 4·与DNA碱基- G，A，T和C之间反应的皮秒脉冲辐解研究。时间分辨观测表明，在6 M H3 PO 4中，H2 PO 4·通过单电子转移（SET）过程形成阳离子自由基，导致腺嘌呤、鸟嘌呤和胸腺嘧啶的单电子氧化;但是，H2 PO 4·与胞嘧啶反应的速率常数太低（< 107 L mol−1 s−1）而无法测量。这些反应的速率受质子化状态和重组能量的基础自由基和磷酸根在6 M H3 PO 4。
In irradiated DNA, by base-to-base and backbone-to-base hole transfer processes, the hole (i.e., the unpaired spin) localizes on the most electropositive base, guanine. Phosphate radicals formed via ionization events in DNA-backbone must play an important role in the backbone-to-base hole transfer process. However, earlier works on irradiated hydrated DNA, on irradiated DNA-models in frozen aqueous solution and in neat dimethyl phosphate showed formation of carbon-centered radicals and not phosphate radicals. Therefore, to model backbone-to-base hole transfer process, we report picosecond pulse radiolysis studies of the reactions between H2PO4• with DNA bases – G, A, T, and C in 6 M H3PO4 at 22 °C. The time-resolved observations show that in 6 M H3PO4, H2PO4• causes one-electron oxidation of adenine, guanine and thymine, by forming the cation radicals via single electron transfer (SET) process; but, the rate constant of the reaction of H2PO4• with cytosine is too low (< 107 L mol−1 s−1) to be measured. The rates of these reactions are influenced by protonation states and reorganization energies of base radicals and of the phosphate radical in 6 M H3PO4.
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影响因子：
15
作者：
Adhikary A;Khanduri D;Sevilla MD
通讯作者：
Sevilla MD
影响因子：
3.3
作者：
Adhikary, Amitava;Becker, David;Palmer, Brian J.;Heizer, Alicia N.;Sevilla, Michael D.
通讯作者：
Sevilla, Michael D.
DOI：
10.1021/jp5028004
发表时间：
2014-05-22
期刊：
The journal of physical chemistry. B
影响因子：
--
作者：
Kumar A;Sevilla MD
通讯作者：
Sevilla MD
影响因子：
2.9
作者：
Ma, Jun;LaVerne, Jay A.;Mostafavi, Mehran
通讯作者：
Mostafavi, Mehran
DOI：
10.1039/ft9928803319
发表时间：
1992-11-21
期刊：
JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS
影响因子：
--
作者：
JIANG, PY;KATSUMURA, Y;YOSHIDA, Y
通讯作者：
YOSHIDA, Y