Terahertz Spectroscopic Analysis in Protein Dynamics: Current Status

Abstract

Proteins play a key role in living organisms. The study of proteins and their dynamics provides information about their functionality, catalysis and potential alterations towards pathological diseases. Several techniques are used for studying protein dynamics, e.g., magnetic resonance, fluorescence imaging techniques, mid-infrared spectroscopy and biochemical assays. Spectroscopic analysis, based on the use of terahertz (THz) radiation with frequencies between 0.1 and 15 THz (3–500 cm−1), was underestimated by the biochemical community. In recent years, however, the potential of THz spectroscopy in the analysis of both simple structures, such as polypeptide molecules, and complex structures, such as protein complexes, has been demonstrated. The THz absorption spectrum provides some information on proteins: for small molecules the THz spectrum is dominated by individual modes related to the presence of hydrogen bonds. For peptides, the spectral information concerns their secondary structure, while for complex proteins such as globular proteins and viral glycoproteins, spectra also provide information on collective modes. In this short review, we discuss the results obtained by THz spectroscopy in the protein dynamics investigations. In particular, we will illustrate advantages and applications of THz spectroscopy, pointing out the complementary information it may provide.

Epithelial Sodium Channel Inhibition by Amiloride Addressed with THz Spectroscopy and Molecular Modeling

“…The function of ion channels involves large conformational transitions that correspond to their low frequency collective normal modes [ 17 ]. These modes fall in the THz frequency domain and are directly accessible through THz spectroscopy experiments [ 7 ]. In this way, THz spectra are highly sensitive to protein conformation and flexibility, which already allowed the characterization of conformational transitions in several proteins [ 7 ].…”

“…For instance, Fourier transform infrared spectroscopy was used to characterize the interaction of channels with ions [ 5 , 6 ]. Terahertz (THz) spectroscopy, using far infrared radiation (0.1–15 THz frequency equivalent to 3–500 cm −1 ), also appears useful for such studies since it directly accesses the low frequency collective modes of proteins [ 7 ]. In a previous study, we proved the efficiency of THz spectroscopy in assessing the N-glycosylation state of the ion channel TRPM8 [ 8 ].…”

High Frequency Electromagnetic Radiation Stimulates Neuronal Growth and Hippocampal Synaptic Transmission

“…Currently, many scholars are beginning to focus on neurons’ responses to terahertz waves, but it is important to consider the safety of terahertz radiation protocols. Although terahertz waves are low in energy and do not ionize matter, this does not mean that they are safe [ 18 , 19 ]. Several studies have shown that terahertz waves’ effects on neurons are two-fold.…”

Terahertz spectra of proteinuria and non-proteinuria

“…Changes of biomolecules, such as change of formation, content, and state, strongly affect the THz spectral characteristics (Niehues et al, 2011;Bye et al, 2014;Klokkou et al, 2022). Recently, THz wave has been proved to have strong interactions with many biochemical molecules such as amino acids, proteins, and deoxyribonucleic acid (DNA) (Esser et al, 2018;Wu et al, 2020;Mancini et al, 2022). Moreover, THz waves have low photon energies (1 THz = 4.1 meV), which is about one million times weaker than the energy of X-ray photons, so it does not cause any harmful ionization in biological molecules (Sirkeli et al, 2018).…”