Barrier-free intermolecular proton transfer in the uracil-glycine complex induced by excess electron attachment
Barrier-free intermolecular proton transfer in the uracil-glycine complex induced by excess electron attachment
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DOI：
10.1140/epjd/e2002-00168-1
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发表时间：
2002-09
期刊：
影响因子：
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通讯作者：
M. Gutowski;I. Dąbkowska;J. Rak;S. Xu;J. Nilles;D. Radisic;K. Bowen Jr.
中科院分区：
文献类型：
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作者：
M. Gutowski;I. Dąbkowska;J. Rak;S. Xu;J. Nilles;D. Radisic;K. Bowen Jr.
尿嘧啶-甘氨酸和尿嘧啶-苯丙氨酸复合物的阴离子的光电子能谱（PES）显示了广泛的功能，在1.8和2.0 eV的最大值。从头算密度泛函B3 LYP和二级Møller-Plesset理论计算结果表明，过剩电子占据定域在尿嘧啶上的π* 轨道.过量的电子附着在配合物上可以诱导甘氨酸的羧基到尿嘧啶的O 8原子的无障碍质子转移（BFPT）。结果表明，尿嘧啶-甘氨酸复合物阴离子的四种最稳定结构可以表征为去质子化甘氨酸阴离子溶剂化的氢化尿嘧啶中性自由基。与甘氨酸和苯丙氨酸的尿嘧啶复合物的PES光谱之间的相似性表明，BFPT也是在后者的阴离子物种的情况下操作。尿嘧啶的O 8原子的BFPT可能与低能电子对核酸碱基的损伤有关，因为在标准Watson-Crick配对方案中，O 8原子参与与腺嘌呤的氢键。
The photoelectron spectra (PES) of anions of uracil-glycine and uracil-phenylalanine complexes reveal broad features with maxima at 1.8 and 2.0 eV. The results ofab initiodensity functional B3LYP and second order Møller-Plesset theory calculations indicate that the excess electron occupies a π*orbital localized on uracil. The excess electron attachment to the complex can induce a barrier-free proton transfer (BFPT) from the carboxylic group of glycine to the O8 atom of uracil. As a result, the four most stable structures of the anion of uracil-glycine complex can be characterized as the neutral radical of hydrogenated uracil solvated by the anion of deprotonated glycine. The similarity between the PES spectra for the uracil complexes with glycine and phenylalanine suggests that the BFPT is also operative in the case of the latter anionic species. The BFPT to the O8 atom of uracil may be related to the damage of nucleic acid bases by low energy electrons because the O8 atom is involved in a hydrogen bond with adenine in the standard Watson-Crick pairing scheme.