Dipolar coupling between electronic transitions of the DNA bases and its relevance to exciton states in double helices
Dipolar coupling between electronic transitions of the DNA bases and its relevance to exciton states in double helices
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DOI：
10.1016/s0301-0104(01)00523-7
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发表时间：
2002-01-01
期刊：
影响因子：
2.3
通讯作者：
Millié, P
中科院分区：
文献类型：
--
作者：
Bouvier, B;Gustavsson, T;Millié, P
本文讨论了DNA核苷最低电子跃迁矩之间的偶极耦合大小及其与双螺旋中弗伦克尔激子态的相关性。核苷的跃迁能和矩是根据在稀水溶液中记录的吸收光谱测定的。根据原子跃迁电荷分布模型，计算了几种典型核苷二聚体的偶极相互作用。（dA）（20）（.）两个特殊双螺旋激子态的性质（dT）（20）和（dAdT）（10）（。）（dAdT）（10），计算时考虑了三个紧密相连的分子电子跃迁（S-1和S-2为腺苷，S，为胸腺嘧啶）。结果表明：(i)振荡强度分布在少数本征态上，（ii）可能发生三种单体电子跃迁的重要混合，（iii）所有本征态在双螺旋的整个长度上都是空间离域的，（iv）两条链上的激子态的范围取决于碱基序列。(C) 2002 Elsevier Science B.V.版权所有
The present communication addresses the question of the magnitude of dipolar coupling between the lowest electronic transition moments of the DNA nucleosides and its relevance to Frenkel exciton states in double helices. The transition energies and moments of the nucleosides are determined from absorption spectra recorded for dilute water solutions. Dipolar interactions are computed for some typical nucleoside dimers according to the atomic transition charge distribution model. The properties of the exciton states of two particular double helices, (dA)(20) (.) (dT)(20) and (dAdT)(10) (.) (dAdT)(10), are calculated considering three closely lying molecular electronic transitions (S-1 and S-2 for adenosine, S, for thymidine). It is shown that (i) the oscillator strength is distributed over a small number of eigenstates, (ii) important mixing of the three monomer electronic transitions may occur, (iii) all eigenstates are spatially delocalised over the whole length of the double helix and (iv) the extent of exciton states over the two strands depends on the base sequence. (C) 2002 Elsevier Science B.V. All rights reserved.