Beetz C P, Ascarelli G, Arnott S
Biophys J. 1979 Oct;28(1):15-26. doi: 10.1016/S0006-3495(79)85155-3.
In this paper we show, based on symmetry considerations, that structural information cannot be obtained from the linear infrared dichroism of the dioxy vibrations of the phosphate group of nucleic acids. Consequently, the discrepancies between the results of x-ray structure measurements and linear dichroism measurements are not meaningful. The linear dichroism measurements are instead important for a calculation of transition dipole moments that involve both the vibrations of all the atoms of the nucleotide and their charges. Independent information on either the atomic displacements contributing to a given vibration or the atomic charges permits a refinement of the unknown quantities. Based on the molecular dynamics calculations of Prohofsky et al., atomic charges of DNA are calculated to reproduce the observed linear dichroism results. Some of the resulting charges are unexpected and may reflect the inadequacy of the molecular dynamic calculation.
在本文中,基于对称性考虑,我们表明无法从核酸磷酸基团双氧振动的线性红外二色性中获取结构信息。因此,X射线结构测量结果与线性二色性测量结果之间的差异并无意义。相反,线性二色性测量对于计算涉及核苷酸所有原子振动及其电荷的跃迁偶极矩很重要。关于对给定振动有贡献的原子位移或原子电荷的独立信息可以优化未知量。基于普罗霍夫斯基等人的分子动力学计算,计算出DNA的原子电荷以重现观察到的线性二色性结果。一些所得电荷出人意料,可能反映了分子动力学计算的不足。