太赫兹光谱在氨基酸分子结构中的应用研究

发布时间：2018-03-24 09:39

本文选题：太赫兹时域光谱　切入点：氨基酸　出处：《华东理工大学》2017年硕士论文

【摘要】：太赫兹(Teraherz,THz)技术在2005年被评为将来会改变世界的十大关键技术之一,是最近发展起来的前沿领域。THz辐射是指频率在远红外区域,位于微波和红外光之间的电磁辐射。物质在这一波段具有丰富的信息,包括氢键、范德华力、晶格振动等,THz光谱能够敏锐地捕捉到这些分子集体运动信息,为生物及药物化学等科研工作提供重要的参考依据。但目前THz光谱的数据库还不够完善,不同的研究工作由于所用的仪器、环境、操作方法的不同,会使实验结果存在差异,本文系统地测定了 20种标准氨基酸的THz光谱。同时,本文利用密度泛函理论(DFT)对部分氨基酸分子结构进行模拟计算,对其THz光谱的特征峰进行了指认,有助于理解特征峰的振动来源,从而理解分子中的弱相互作用力与THz指纹谱之间的关系。利用太赫兹时域光谱(THz-TDS)研究了 20种标准α-氨基酸的THz光谱,除甘氨酸没有手性以外,对每种氨基酸的L-,D-型以及外消旋化合物都进行了表征,并通过X射线粉末衍射实验(PXRD)与其分子结构相关联,总结了其中的相关规律,补充了这一领域中的THz光谱数据库,为今后的包括蛋白质、核酸等生物大分子的研究打下基础。结合DFT理论,利用Material Studio软件,对DL-型,L-型丝氨酸的THz光谱进行了模拟计算,并从键长、键角、和氢键距离等三个方面评估了模拟计算的可靠性,计算结果显示分子在该波段的光谱特征峰主要来自于分子的集体转动、扭曲和分子的平移。利用THz-TDS研究了室温及低温环境下的L-苯丙氨酸及其一水合物在0.5-4.5 THz范围内的低频振动特征,两种物质表现出了不同的特征吸收。基于DFT理论模拟了分子的振动模式和理论光谱,与实验观测的结果吻合良好。L-苯丙氨酸的特征峰主要来自于分子的集体振动,而L-苯丙氨酸—水合物的特征峰主要来自于氢键的振动以及水分子和苯丙氨酸分子间的相互作用。
[Abstract]:Teraherzia THz technology was named in 2005 as one of the top ten key technologies that will change the world in the future. It is the recently developed frontier. THz radiation refers to the frequency in the far infrared region. Electromagnetic radiation between microwave and infrared light. Matter has a wealth of information in this band, including hydrogen bonds, van der Waals force, lattice vibration and so on. This paper provides an important reference for scientific research work such as biology and pharmacochemistry. But the database of THz spectrum is not perfect at present. Because of the different instruments, environment and operation methods used in different research work, the experimental results will be different. In this paper, the THz spectra of 20 kinds of standard amino acids have been systematically determined. At the same time, the molecular structure of some amino acids has been simulated by density functional theory (DFT), and the characteristic peaks of THz spectra have been identified. It is helpful to understand the vibrational source of the characteristic peaks and to understand the relationship between the weak interaction force in the molecule and the THz fingerprint spectrum. The THz spectra of 20 standard 伪 -amino acids have been studied by using THz TDSs. Except glycine, there is no chirality. The L-D- type and racemic compounds of each amino acid were characterized, and their molecular structures were correlated with PXRD by X-ray powder diffraction (XRD). The related laws were summarized and the THz spectral database in this field was supplemented. Based on the DFT theory and Material Studio software, the THz spectra of DL- L- serine were simulated and calculated from the bond length and bond angle. And hydrogen bond distance, the reliability of the simulation calculation is evaluated. The results show that the spectral characteristic peak of the molecule in this band is mainly from the collective rotation of the molecule. THz-TDS was used to study the low frequency vibration characteristics of L-phenylalanine and its monohydrate in the range of 0.5-4.5 THz. Based on the DFT theory, the vibrational modes and theoretical spectra of the molecules are simulated. The characteristic peaks of L- phenylalanine mainly come from the collective vibration of the molecules, which are in good agreement with the experimental results. The characteristic peaks of L-phenylalanine hydrate are mainly from the vibration of hydrogen bond and the interaction between water molecule and phenylalanine molecule.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O629.71;O657.3

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