胸腺嘧啶紫外损伤与自修复机理的计算机模拟

Computer simulation for photo damage and self-repair of thymine

为了研究DNA分子紫外光辐射下光损伤和自修复,采用半经典动力学方法模拟了胸腺嘧啶分子激发与失活过程。模拟脉冲频率为5.0 eV,fwhm=50 fs。模拟发现胸腺嘧啶在紫外辐射下会生成电子激发态,导致分子结构畸变,可能引发突变。由于激发态寿命极短,激发态的胸腺嘧啶分子通过H6原子和C6原子的畸变发生无辐射失活而衰减至基态,恢复其初始的平面结构,从而最大程度地避免了紫外损伤。本研究可为皮肤癌等疾病的预防提供一定的理论支持。

A semiclassical dynamics simulation study is reported for excitement and deactivation of thymine molecule in order to research photo damage and self-repairs of DNA under UV irradiation. The laser pulse used to simulations is 5.0 eV with fwhm（ full width of half maxium） of 50 femtoseconds. The simulation finds that the thymine molecule will be induced to excited state by UV irradiation. The deformations of thymine molecule in excited state maybe result in gene mutation. The non-radiation transition of excited thymine via deformation of C6 atom and H6 atom occurs within ultra-short timescale, lead thymine to its initial planar geometry and avoid UV photo damage. This research will provide theoretical supporting for prevention of skin cancer.