Complex Formation between a DNA Duplex and Lipid-like Spermine Derivatives: Hydrophobic Protection of DNA from One-Electron Oxidation
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- 作者：Huachuan Cao and Gary B. Schuster
- 刊名：Bioconjugate Chemistry
- 出版年：2005
- 出版时间：July 2005
- 年：2005
- 卷：16
- 期：4
- 页码：820 - 826
- 全文大小：234K
- 年卷期：v.16,no.4(July 2005)
- ISSN：1520-4812
文摘
The one-electron oxidation of DNA leads to formation of a nucleobase radical cation that can migrateto a distant site where it is trapped by H2O or O2 to form a "damaged" guanine that is revealed asstrand cleavage when the irradiated sample is treated with piperidine. We prepared a series of alkyl-substituted spermine derivatives and assessed their effect on the oxidative reactions of DNA inducedby photoexcitation of a covalently linked anthraquinone derivative. The spermine compounds arepolycations and bind nonselectively to DNA. When the spermine derivative is substituted with C8alkyl chains, it shows lipid-like properties. The reaction of the radical cation at guanine is affected bythis lipid-like spermine. The distance dependence of the migration process becomes weaker, and theefficiency of strand cleavage is reduced. These results are attributed to the formation of a hydrophobiclayer on the DNA that restricts access of H2O to the nucleobase radical cation.