Direct observation of the hole protonation state and hole localization site in DNA-oligomers.
Direct observation of the hole protonation state and hole localization site in DNA-oligomers.
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DOI：
10.1021/ja9014869
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发表时间：
2009-06-24
影响因子：
15
通讯作者：
Sevilla MD
中科院分区：
文献类型：
--
作者：
Adhikary A;Khanduri D;Sevilla MD
在这项工作中，研究表明，在dna低聚物中加入8-氘鸟嘌呤（G*）片段，可以在77 K时直接测定(i) dsDNA中特定碱基位点上的空穴（即自由基位点）的位置，甚至在G的堆中，以及（ii）该位点上空穴的质子化状态。这些发现是基于我们的工作，并证明了在dGuo中鸟嘌呤部分的C-8选择性氘化导致鸟嘌呤阳离子自由基（G*•+）的ESR信号，这很容易与未氘化的鸟嘌呤阳离子自由基（G•+）区分。G*•+也很容易与其共轭碱（n1 -去质子化自由基G*(−H)•）区分。我们的ESR结果清楚地表明，在77 K时(i)双链dna低聚物中的单电子氧化鸟嘌呤作为去质子化的中性自由基G（−H）•存在，这是由于质子容易转移到氢键胞嘧啶上的结果；（ii）在一些具有GGG序列的dna低聚物中，空穴优先位于5 '端。
In this work, it is shown that the incorporation of an 8-deuteroguanine (G*) moiety in DNA-oligomers allows for direct determination at 77 K of (i) the location of holes (i.e., the radical site) within dsDNA at specific base sites, even within stacks of G, as well as (ii) the protonation state of the hole at that site. These findings are based on our work and demonstrate that selective deuteration at C-8 on guanine moiety in dGuo results in an ESR signal from the guanine cation radical (G*•+) which is easily distinguishable from that of the undeuterated guanine cation radical (G•+). G*•+ is also found to be easily distinguishable from its conjugate base, the N1-deprotonated radical, G*(−H)•. Our ESR results clearly establish that at 77 K (i) one-electron oxidized guanine in double stranded DNA-oligomers exists as the deprotonated neutral radical G(−H)• as a result of facile proton transfer to the hydrogen bonded cytosine, and (ii) the hole is preferentially located at the 5′-end in several ds DNA-oligomers with a GGG sequence.
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影响因子：
4.3
作者：
Gervasio, FL;Laio, A;Parrinello, M
通讯作者：
Parrinello, M
影响因子：
15
作者：
Adhikary A;Kumar A;Khanduri D;Sevilla MD
通讯作者：
Sevilla MD
DOI：
10.1073/pnas.96.15.8353
发表时间：
1999-07-20
影响因子：
11.1
作者：
Henderson, PT;Jones, D;Schuster, GB
通讯作者：
Schuster, GB
影响因子：
3.3
作者：
Debije, MG;Bernhard, WA
通讯作者：
Bernhard, WA
影响因子：
15
作者：
Hickerson, RP;Prat, F;Burrows, CJ
通讯作者：
Burrows, CJ