EVALUATING RADIATION CHANGE IN NUCLEIC ACIDS

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。本课题的研究重点是电离辐射对DNA结构和能量学的影响。报道了鸟嘌呤-胞嘧啶碱基对电离的从头算研究结果。双质子转移产生的典型GC碱基对和稀有GC碱基对都受到电子的包裹，并观察到几何和能量的变化。利用5个基集(6-31G(d)、6-311G（d)、6-311G（d,p）、aug-cc-pVDZ和dzp++）对这些碱基对进行B3LYP水平的理论优化。当电子附着时，两种物质都表现出相当大的非平面性。此外，电子亲和和相对能量表明，在这些条件下，稀有形式可能更有利。这可能表明DNA在添加一个电子时利用了一种新的机制。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The focus of this project is the effect of ionizing radiation on DNA structure and energetics. The results of an ab initio study of ionization of guanine-cytosine base pair are reported. Both the canonical GC base pair and the rare GC base pair, created by a double proton transfer are subject to the inclusion of an electron and the geometric and energetic changes were observed. These base pairs were allowed to optimized at the B3LYP level of theory utilizing five basis sets (6-31G(d), 6-311G(d), 6-311G(d,p), aug-cc-pVDZ, and DZP++). Both species showed considerable nonplanarity when the electron is attached. Futhermore, the electron affinities and relative energies show that the rare form may be favored under these conditions. This may suggest a new mechanism that DNA utilizes upon addition of an electron.