Long-distance charge transport in duplex DNA: The phonon-assisted polaron-like hopping mechanism
Long-distance charge transport in duplex DNA: The phonon-assisted polaron-like hopping mechanism
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DOI：
10.1073/pnas.96.15.8353
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发表时间：
1999-07-20
影响因子：
11.1
通讯作者：
Schuster, GB
中科院分区：
文献类型：
--
作者：
Henderson, PT;Jones, D;Schuster, GB
通过PCR合成了一个含有60个碱基对的蒽醌连接的双链DNA寡聚体。与含醌链互补的链具有四个孤立的GG步骤，其充当迁移自由基阳离子的陷阱。醌的辐射导致电子从DNA转移到醌，形成蒽醌自由基阴离子和碱自由基阳离子。自由基阳离子迁移通过DNA，引起GG步骤的反应，显示为链断裂。链裂解的效率福尔斯随离醌的距离呈指数下降（斜率为-0.02埃（-1））。这一发现需要重新解释提出的机制，自由基阳离子迁移的DNA。我们建议，自由基阳离子形成自陷极化子迁移热激活跳跃。
An anthraquinone-linked duplex DNA oligomer containing 60 base pairs was synthesized by PCR. The strand complementary to the quinone-containing strand has four isolated GG steps, which serve as traps for a migrating radical cation. Irradiation of the quinone leads to electron transfer from the DNA to the quinone forming the anthraquinone radical anion and a base radical cation. The radical cation migrates through the DNA, causing reaction at GG steps revealed as strand breaks. The efficiency of strand cleavage falls off exponentially with distance from the quinone (slope -0.02 Angstrom(-1)). This finding necessitates reinterpretation of mechanisms proposed for radical cation migration in DNA. We propose that radical cations form self-trapped polarons that migrate by thermally activated hopping.