Tunneling energy effects on GC oxidation in DNA
Tunneling energy effects on GC oxidation in DNA
复制标题
隧道能量对 DNA GC 氧化的影响
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
D. Beratan
中科院分区：
文献类型：
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作者：
G. Tong;and Igor V. Kurnikov;D. Beratan
对DNA中空穴转移反应的空穴介导的电子耦合、重组能和电子转移(ET)速率进行了理论研究。研究发现，电子转移速率主要取决于施主/受主能隙和介电基团之间的能隙，即隧道能隙。在模型结构中，当隧道能隙从0.3eV到0.8eV(我们认为这是最近的实验中探索的GC氧化的能隙范围)时，计算出的GC碱基对(和pi电子D/A对)之间空穴转移的电子耦合平方β的距离衰减指数在0.95A-1.5A-1之间。结果表明，隧道能隙依赖于ET重组能，对于超过1−5个碱基对的ET，该重组能随着距离的增加而迅速增长。计入这些空穴转移反应的重组能与距离的关系后，隧道传输率的明显衰减指数为∼1.5−2.5A-1。我们表明，在DNA中观察到的ET率...
Hole-mediated electronic couplings, reorganization energies, and electron transfer (ET) rates are examined theoretically for hole-transfer reactions in DNA. Electron transfer rates are found to depend critically on the energy gap between the donor/acceptor states and the intervening basesthe tunneling energy gap. The calculated distance decay exponent for the square of the electronic coupling, β, for hole transfer between GC base pairs (and pi-electron D/A pairs) ranges from 0.95 to 1.5 A-1 in the model structures as the tunneling energy gap varies from 0.3 to 0.8 eV (which we argue is the range of energy gaps for GC oxidation probed in recent experiments). We show that the tunneling energy gap depends on the ET reorganization energy, which itself grows rapidly with distance for ET over 1−5 base pairs. Inclusion of the distance dependence of reorganization energies for these hole transfer reactions gives the tunneling rates an apparent decay exponent of ∼1.5−2.5 A-1. We show that ET rates observed in DNA ...