Exploration of the excited-state dynamics of amino acids and peptides by ab initio electronic-structure calculations

通过从头算电子结构计算探索氨基酸和肽的激发态动力学

• 批准号: 28811318
• 负责人: Professor Dr. Wolfgang Domcke
• 金额: --
• 依托单位: Department of Chemistry and Biochemistry
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2012-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/28811318?language=en
• 关键词: Exploration; excited; state; dynamics; amino

The structure-selective photophysical properties of isolated guanine-cytosine (GC) and adenine-thymine (AT) DNA base pairs will be explored by ab initio electronic-structure calculations. The calculations are intended to guide and support spectroscopic investigations of the lowest-energy conformers of GC and AT by M.S. de Vries and collaborators. The UV spectra of GC provide evidence for a very efficient excited-state deactivation mechanism that is specific for the Watson-Crick tautomer of GC and may be essential for the photostability of DNA (A. Abo-Riziq et al., PNAS 102, 20 (2005)). Preliminary computational evidence hints at the importance of electron-driven inter-base proton-transfer processes for the ultrafast deactivation of the UV absorbing states of GC (A.L. Sobolewski et al., PNAS 102, 17903 (2005)). In this project, we shall perform more comprehensive and more accurate calculations of excited-state potential-energy surfaces, photochemical reaction paths and conical intersections for the lowest-energy tautomers of GC and AT. In addition, the timescales of the relevant primary processes will be estimated via the determination of energy barriers and the simulation of nonadiabatic quantum wave-packet dynamics at conical intersections. Summary of the proposed interaction The spectroscopic investigations will be performed in the research group of M. S. de Vries in Santa Barbara. The computational studies will be performed, in close coordination with the spectroscopic studies, in Garching in the group of W. Domcke. The role of the computations is two-fold: they will (i) guide the experimental studies in the selection of the most interesting systems and the most appropriate spectroscopic techniques and (ii) they will provide support for the interpretation of the experimental signals. Much of the exchange of information will occur by email or file transfer. For the coordination of the research, each of the principal investigators will visit the partner group once per year for one week.

通过从头算电子结构计算，探讨了鸟嘌呤-胞嘧啶（GC）和腺嘌呤-胸腺嘧啶（AT）DNA碱基对的结构选择性物理性质。计算结果可用于指导和支持质谱法对GC和AT的最低能量构象的光谱研究。德弗里斯及其合作者。GC的UV光谱为非常有效的激发态失活机制提供了证据，该机制对GC的沃森-克里克互变异构体是特异性的，并且可能对DNA的光稳定性是必不可少的（A. Riziq等人，PNAS 102，20（2005））。初步的计算证据暗示了电子驱动的碱基间质子转移过程对于GC的UV吸收态的超快失活的重要性（A. L. Sobolewski等人，PNAS 102，17903（2005））。在本项目中，我们将对GC和AT的最低能量互变异构体的激发态势能面、光化学反应路径和锥形交叉点进行更全面、更精确的计算。此外，相关的主要过程的时间尺度将估计通过确定的能量障碍和非绝热量子波包动力学在圆锥路口的模拟。建议的相互作用的总结光谱研究将在M。S.圣巴巴拉的弗里斯。计算研究将在Garching的W.多姆克计算的作用是双重的：它们将（i）指导实验研究选择最有趣的系统和最合适的光谱技术，（ii）它们将为实验信号的解释提供支持。大部分信息交换将通过电子邮件或文件传输进行。为了协调研究，每个主要研究者每年将访问合作伙伴小组一次，为期一周。