基于分子对接的类二恶英类多氯联苯的拉曼光谱增强

Raman Spectra Enhancement of Dioxin-like Polychlorinated Biphenyls(PCBs) Based on Molecular Docking

为了从分子结构角度找到可以增强类二恶英类多氯联苯(PCBs)的拉曼光谱振动强度的结构变量,利用密度泛函理论(DFT)在B3LYP/6-31G(d)水平下对13种类PCBs结构进行优化,通过分子对接技术提取13种PCBs与联苯双加氧酶(Bpha,PDB∶3GZX)对接后的PCBs分子结构,并计算了气态环境下对接前后PCBs分子的拉曼光谱振动强度和频率。研究结果表明:13种PCBs的拉曼振动归属为苯环变形、C—C伸缩、C—H摇摆、C—H伸缩以及各种形式的耦合,其中拉曼光谱频率在1 632.77~1 652.06 cm-1之间的振动最强,苯环变形为特征振动;对接后PCBs的二面角大小有明显的改变,导致拉曼振动强度提高2.9%~213.98%,频率在1631.57~1 651.94 cm-1之间的拉曼峰整体发生蓝移,二面角大小与拉曼振动强度呈现一定程度的线性关系,随二面角逐渐减小,拉曼振动增强。实验结果表明,可通过调整PCBs的二面角大小达到提升PCBs辨识灵敏度的目的,并为PCBs拉曼光谱检测提供理论依据。

To find the structural variables that can enhance the vibrational intensity of Raman spectra of dioxin like polychlorinated biphenyls(PCBs)from the molecular structure point of view,the structures of 13 dioxin-like polychlorinated biphenyls(PCBs)were optimized by density functional theory(DFT)at B3LYP/6-31G(d)level.The molecular structures of 13 kinds of PCBs were extracted after docking with biphenyl dioxygenase(Bpha,PDB∶3GZX)by molecular docking technique,and the Raman spectra vibration intensity and frequency of the PCBs before and after docking were calculated.The results show that the Raman vibrations of 13 kinds of PCBs are benzene ring deformation,C-C stretching,C-H swing,C-H stretching and various forms of coupling,the Raman vibration intensity is the strongest between 1 632.77-1 652.06 cm-1 and the benzene ring deformation is the characteristic vibration.The results of molecular docking show that the dihedral angle of PCBs after docking has obvious change,resulting in the increase of the Raman vibration intensity by 2.9%-213.98%,the Raman peaks between 1 631.57-1 651.94 cm-1 blue shifting.The dihedral angle and the Raman vibration intensity show a certain degree of linear relationship.The Raman vibration intensity is enhanced with the decreasing of the dihedral angle.It can be used to improve the sensitivity of PCBs identification by adjusting the dihedral angle of PCBs.The results can provide a theoretical basis for the detection of PCBs Raman spectroscopy.