Synthesis and Photooxidation of Oligodeoxynucleotides Containing 5-Dimethylaminocytosine as an Efficient Hole-Trapping Site in the Positive-Charge Transfer through DNA duplexes
Synthesis and Photooxidation of Oligodeoxynucleotides Containing 5-Dimethylaminocytosine as an Efficient Hole-Trapping Site in the Positive-Charge Transfer through DNA duplexes
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含有 5-二甲氨基胞嘧啶的寡脱氧核苷酸的合成和光氧化作为 DNA 双链体正电荷转移中的有效空穴捕获位点
DOI：
10.1039/c2ob06642d
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
S
中科院分区：
文献类型：
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作者：
Yamada;H.; Kurata;M.; Tanabe;K.; Ito;T.; Nishimoto;S
我们设计并合成了含5-二甲氨基胞嘧啶（DMAC）的DNA双链体，研究了C（5）-取代胞嘧啶碱基对DNA双链体中正电荷（空穴）转移和捕获的影响。荧光猝灭实验表明，与其他天然核碱基相比，DMAC碱基更容易被单电子氧化成自由基阳离子中间体。在光照射的双链体含有DMAC，光敏剂注入的孔迁移通过DNA碱基，并被有效地捕获在DMAC网站，在那里发生了增强的氧化链裂解热哌啶处理。通过空穴转移形成的DMAC自由基阳离子可以经历特定的水合作用和随后的分子氧加成，从而导致其分解，随后在DMAC位点处发生主要的链裂解。这一显着的性质表明，修饰的胞嘧啶DMAC可以作为一个有效的空穴捕获位点在DNA双链体的正电荷转移。
We have designed and synthesized DNA duplexes containing 5-dimethylaminocytosine (DMAC) to investigate the effects of C(5)-substituted cytosine bases on the transfer and trapping of positive charge (holes) in DNA duplexes. Fluorescence quenching experiments revealed that a DMAC base is more readily one-electron oxidized into a radical cation intermediate as compared with other natural nucleobases. Upon photoirradiation of the duplexes containing DMAC, the photosensitizer-injected hole migrated through the DNA bases and was trapped efficiently at the DMAC sites, where an enhanced oxidative strand cleavage occurred by hot piperidine treatment. The DMAC radical cation formed by hole transfer may undergo specific hydration and subsequent addition of molecular oxygen, thereby leading to its decomposition followed by a predominant strand cleavage at the DMAC site. This remarkable property suggests that the modified cytosine DMAC can function as an efficient hole-trapping site in the positive-charge transfer in DNA duplexes.