强耦合多发色体系的激子模型：鸟嘌呤四链体的电子圆二色谱光谱作为测试案例,Journal of Chemical Theory and Computation

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强耦合多发色体系的激子模型：鸟嘌呤四链体的电子圆二色谱光谱作为测试案例
Journal of Chemical Theory and Computation ( IF 5.7 ) Pub Date : 2020-12-30 , DOI: 10.1021/acs.jctc.0c01100
James A. Green ₁ , Haritha Asha ₁ , Fabrizio Santoro ₂ , Roberto Improta ₁

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在此，我们提出一种基于碎片的绝热作用的通用且灵活的方法，该方法结合了电荷转移状态，并显着提高了发色团非常接近的系统的激子哈密顿量的可靠性。此模型（FrDEx）用于计算折叠成四重螺旋（GQs）的两个富含鸟嘌呤的原型原型鸟嘌呤DNA序列的电子圆二色性和吸收光谱，即人端粒序列的片段（Tel21，反平行）和（TGGGGT ）₄（TG4T，并行）。对Tel21和TG4T的不同子集（从二聚体到四聚体）的计算表明，FrDEx提供的光谱接近于参考全量子力学（QM）的光谱（通过时变密度泛函理论获得），相对于“标准”，有了显着改进。激子哈密顿主义者。此外，这些测试可以确定整个GQ的最具成本效益的过程。Tel21和TG4T的FrDEx光谱也与QM和实验的光谱相吻合，并提供了有趣的见解，以了解调制光谱信号的化学物理效应。从DNA到（光电）电子聚合物，FrDEx可以用于研究许多其他生物和纳米技术材料。

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Excitonic Model for Strongly Coupled Multichromophoric Systems: The Electronic Circular Dichroism Spectra of Guanine Quadruplexes as Test Cases

We here propose a general and flexible approach, based on fragment diabatization, which incorporates charge transfer states and significantly increases the reliability of excitonic Hamiltonians for systems where the chromophores are very close. This model (FrDEx) is used to compute the electronic circular dichroism and absorption spectra of two prototype guanine-rich DNA sequences folded in quadruple helices (GQs), i.e., a fragment of the human telomeric sequence (Tel21, antiparallel), and (TGGGGT)₄ (TG4T, parallel). Calculations on different subsets of Tel21 and TG4T, from dimers to tetramers, show that FrDEx provides spectra close to the reference full quantum mechanical (QM) ones (obtained with time-dependent density functional theory), with significant improvements with respect to “standard” excitonic Hamiltonians. Furthermore, these tests enable the most cost-effective procedure for the whole GQ to be determined. FrDEx spectra of Tel21 and TG4T are also in good agreement with the QM and experimental ones and give access to interesting insights into the chemical–physical effects modulating the spectral signals. FrDEx could be profitably used to investigate many other biological and nanotechnological materials, from DNA to (opto)electronic polymers.

更新日期：2020-12-30

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