Shen Jianxiong, Zhu Zhongjie, Zhang Zongchang, Guo Cong, Zhang Jianbing, Ren Guanhua, Chen Ligang, Li Shaoping, Zhao Hongwei
School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China; Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China; Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Science, Shanghai 201800, China.
Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China; Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Science, Shanghai 201800, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2021 Feb 15;247:119141. doi: 10.1016/j.saa.2020.119141. Epub 2020 Nov 4.
Melatonin (MLT), as a neurotransmitter and an endogenous neurohormone, plays an important role in physiological functions through interactions with specific receptors. The conformations of MLT are closely related to its biological activities and functions. However, the internal relationship between the structure and interaction of MLT and its allosteric transition remains unclear. In this work, we obtain the broadband fingerprint terahertz (THz) spectrum of MLT in the range of 0.5-18 THz using the air-plasma terahertz time-domain spectroscopy (THz-TDS) system. DFT calculations are employed to analyze the vibration characteristics of MLT. The result shows that the low-frequency vibrations mainly come from the strong coupling between inter- and intramolecular vibrations, and the contribution of intramolecular vibrations gradually dominates with increasing frequency. Meanwhile, the local vibrations of the different functional groups distribute widely in the THz low-frequency band, relating to the diversity of conformational changes in the molecule. The intermolecular hydrogen bonds (HBs) have distinct resonant responses and play critical roles in the THz low-frequency vibrations. The study reveals the complex characteristics of the resonant coupling of MLT with THz electromagnetic waves. The results will help to understand the conformational preferences of MLT in neural signal transmission processes.
褪黑素（MLT）作为一种神经递质和内源性神经激素，通过与特定受体相互作用在生理功能中发挥重要作用。MLT的构象与其生物活性和功能密切相关。然而，MLT的结构与相互作用及其变构转变之间的内在关系仍不清楚。在这项工作中，我们使用空气等离子体太赫兹时域光谱（THz-TDS）系统获得了0.5 - 18 THz范围内MLT的宽带指纹太赫兹（THz）光谱。采用密度泛函理论（DFT）计算来分析MLT的振动特性。结果表明，低频振动主要来自分子间和分子内振动的强耦合，并且随着频率增加分子内振动的贡献逐渐占主导。同时，不同官能团的局部振动在太赫兹低频带中广泛分布，这与分子构象变化的多样性有关。分子间氢键（HBs）具有明显的共振响应，并且在太赫兹低频振动中起关键作用。该研究揭示了MLT与太赫兹电磁波共振耦合的复杂特性。这些结果将有助于理解MLT在神经信号传递过程中的构象偏好。
