双链DNA中自由基阳离子迁移的碱基序列效应：对类极化子跳跃模型的支持

Base sequence effects in radical cation migration in duplex DNA: support for the polaron-like hopping model.

作者信息

Liu Chu-Sheng, Schuster Gary B

机构信息

School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta 30332, USA.

出版信息

J Am Chem Soc. 2003 May 21;125(20):6098-102. doi: 10.1021/ja029333h.

DOI:10.1021/ja029333h

PMID:12785840

Abstract

A series of anthraquinone-linked (AQ) duplex DNA oligomers were prepared and investigated. Irradiation of the AQ injects a radical cation into the DNA. The radical cation migrates through the DNA and reacts selectively at GG steps, which leads to strand cleavage after treatment with piperidine. The oligomers investigated in this work were selected to assess the effect on long-distance charge transport of placing a T base (or bases) in a strand of repeating purine bases. With notable exceptions, the amount of strand scission decreases with the distance between the AQ and the GG step. The results are consistent only with models for long-distance transport, such as thermally activated polaron-like hopping, that incorporate radical cation delocalization over two or more adjacent bases.

摘要

制备并研究了一系列蒽醌连接（AQ）的双链DNA寡聚物。对AQ进行辐照会将一个自由基阳离子注入到DNA中。该自由基阳离子在DNA中迁移，并在GG位点处发生选择性反应，这导致在用哌啶处理后发生链断裂。在这项工作中所研究的寡聚物被选来评估在重复嘌呤碱基链中放置一个T碱基（或多个碱基）对长距离电荷传输的影响。除了一些显著的例外情况，链断裂的量随着AQ与GG位点之间的距离增加而减少。这些结果仅与长距离传输模型一致，比如热激活的类极化子跳跃模型，该模型考虑了自由基阳离子在两个或更多相邻碱基上的离域化。