首页|Evaluation of formation and proportion of secondary structure in gamma-polyglutamic acid by terahertz time-domain spectroscopy

Evaluation of formation and proportion of secondary structure in gamma-polyglutamic acid by terahertz time-domain spectroscopy

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  • NSTL
  • Elsevier
The study of secondary structure is essential for understanding peptides and proteins. Here, we measured the terahertz (THz) spectra of gamma-polyglutamic acid (gamma-PGA) dominated by alpha-helix and random coil (RC) respectively. The alpha-helix has two absorption peaks in the THz region, but no absorption peak is observed in the RC conformation. We believe this is because the hydrogen bonding effect leads to a higher orientation in the helix-dominated gamma-PGA. At lower pH, the absorption intensity of gamma-PGA increases with the induction time. Similar changes were obtained in the Fourier infrared spectroscopy (FTIR). Through the correlation analysis of THz and IR spectroscopy, it is found that the characteristic peak at 1.2 THz can be used as a sensitive indicator of the intermediate conformation of the alpha-helical structure. In addition, the transformation of alpha-helix-RC conformation is related to the peak intensity at 1.99 THz (R-2 = 0.991), which preliminarily indicates that terahertz time-domain spectroscopy (THz-TDS) has the potential to become a new effective method for characterizing and evaluating secondary structure. (C) 2022 Elsevier B.V. All rights reserved.

Terahertz spectroscopyFourier infrared spectroscopygamma-polyglutamic acidSecondary structureL-GLUTAMIC ACIDPOLY-L-LYSINEPOLY(L-GLUTAMIC ACID)ALPHA-HELIXBETA-SHEETINTERMOLECULAR INTERACTIONS2-DIMENSIONAL RAMANCOIL TRANSITIONPOLYPEPTIDESMODEL

Zhu, Zhenqi、Bian, Yujing、Zhang, Xun、Zeng, Ruonan、Yang, Bin

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Zhejiang Sci Tech Univ

2022

10.1016/j.saa.2022.120940

Spectrochimica acta

Spectrochimica acta

ISSN：1386-1425
年,卷(期)：2022.271
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