Geller M, Lesyng B
Biochim Biophys Acta. 1975 Nov 4;407(4):407-19.
A theoretical investigation of the conformation of the amino group in cytosine has been performed by the CNDO/2 and INDO methods. The results suggest that from the energetical point of view the conformation of the amino group is not stable in the course of rotation. It changes its hybridization from sp2-like in the planar case to sp3-like in the transition state. The physical basis of the barrier to rotation of this group around the C4-N7 bond are discussed. Some comments on the solvent dependence of the electronic absorption spectra of cytosine are presented.
已通过CNDO/2和INDO方法对胞嘧啶中氨基的构象进行了理论研究。结果表明，从能量角度来看，氨基在旋转过程中的构象不稳定。它的杂化从平面情况下的类似sp2变为过渡态下的类似sp3。讨论了该基团围绕C4-N7键旋转势垒的物理基础。还对胞嘧啶电子吸收光谱的溶剂依赖性提出了一些看法。
