Hole Trapping at N6-Cyclopropyldeoxyadenosine Suggests a Direct Contribution of Adenine Bases to Hole Transport through DNA
详细信息 查看全文
- 作者：Chikara Dohno ; Atsushi Ogawa ; Kazuhiko Nakatani ; and Isao Saito
- 刊名：Journal of the American Chemical Society
- 出版年：2003
- 出版时间：August 27, 2003
- 年：2003
- 卷：125
- 期：34
- 页码：10154 - 10155
- 全文大小：55K
- 年卷期：v.125,no.34(August 27, 2003)
- ISSN：1520-5126
文摘
Recent studies predict that adenine radical cation (A
+) contributes to the hole-trapping process through long A/T sequences and exists as a real chemical intermediate. However, the experimental evidence for the existence of A+ has not been observed in the DNA-mediated hole transport reaction. To examine the direct contribution of A+, we have developed a novel hole-trapping nucleobase N6-cyclopropyldeoxyadenosine (dCPA) which possesses a cyclopropyl group as a radical trapping device. One-electron oxidation of dCPA revealed that dCPA radical cation undergoes a rapid cyclopropane ring opening. With the use of the dCPA-containing DNA, we have demonstrated that the migrating hole was trapped at CPA incorporated into a long A/T bridge between two GG sites. The present results indicate that nucleobases possessing ionization potential higher than that of dG, such as dA, are able to participate directly in the multistep hopping mechanism.
+) contributes to the hole-trapping process through long A/T sequences and exists as a real chemical intermediate. However, the experimental evidence for the existence of A+ has not been observed in the DNA-mediated hole transport reaction. To examine the direct contribution of A+, we have developed a novel hole-trapping nucleobase N6-cyclopropyldeoxyadenosine (dCPA) which possesses a cyclopropyl group as a radical trapping device. One-electron oxidation of dCPA revealed that dCPA radical cation undergoes a rapid cyclopropane ring opening. With the use of the dCPA-containing DNA, we have demonstrated that the migrating hole was trapped at CPA incorporated into a long A/T bridge between two GG sites. The present results indicate that nucleobases possessing ionization potential higher than that of dG, such as dA, are able to participate directly in the multistep hopping mechanism.