Ab initio study of the structural, tautomeric, pairing, and electronic properties of seleno-derivatives of thymine.
Ab initio study of the structural, tautomeric, pairing, and electronic properties of seleno-derivatives of thymine.
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DOI：
10.1021/jp9057077
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发表时间：
2009-10
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影响因子：
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通讯作者：
Á. Vázquez-Mayagoitia;Óscar Huertas;G. Brancolini;A. Migliore;B. Sumpter;M. Orozco;F. Luque;R. Di Felice;M. Fuentes-Cabrera
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文献类型：
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作者：
Á. Vázquez-Mayagoitia;Óscar Huertas;G. Brancolini;A. Migliore;B. Sumpter;M. Orozco;F. Luque;R. Di Felice;M. Fuentes-Cabrera
通过从头算计算技术研究了胸腺嘧啶（T）的一种硒衍生物（在此记为4SeT，是通过用Se取代T中的O4而产生的）的结构、互变异构、氢键、堆积和电子性质。T和4SeT的结构性质非常相似，几何差异主要局限于C - Se键的相邻环境。对于T和4SeT，在气相和水溶液中，规范的“酮式”异构体都是最稳定的互变异构体。有人认为，在将4SeT掺入双链时，两种相反趋势之间的竞争，即碱基配对能力的降低和堆积相互作用的增加，可能解释了硒衍生物双链（Se - DNA）与其天然对应物相似的实验熔点。有趣的是，潜在的电子结构表明，用Se取代O4促进了最高占据分子轨道 - 最低未占分子轨道（HOMO - LUMO）能隙的减小以及面间耦合的增加，这表明Se - DNA可能对纳米器件应用有用。4SeT…A堆积碱基对之间的转移积分大于类似堆积的天然T…A对所确定的值这一事实进一步支持了这一发现。
The structural, tautomeric, hydrogen-bonding, stacking, and electronic properties of a seleno-derivative of thymine (T), denoted here as 4SeT and created by replacing O4 in T with Se, are investigated by means of ab initio computational techniques. The structural properties of T and 4SeT are very similar, and the geometrical differences are mainly limited to the adjacent environment of the C-Se bond. The canonical "keto" form is the most stable tautomer, in the gas phase and in aqueous solution, for both T and 4SeT. It is argued that the competition between two opposite trends, i.e., a decrease in the base-pairing ability and an increase of the stacking interaction upon incorporation of 4SeT into a duplex, likely explains the similar experimental melting points of a seleno-derivative duplex (Se-DNA) and its native counterpart. Interestingly, the underlying electronic structure shows that replacement of O4 with Se promotes a reduction in the HOMO-LUMO gap and an increase in interplane coupling, which suggests that Se-DNA could be potentially useful for nanodevice applications. This finding is further supported by the fact that transfer integrals between 4SeT...A stacked base pairs are larger than those determined for similarly stacked natural T...A pairs.