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Volume 24 (2010), Issue 1-2, Pages 149-152

Structural fluctuation of proteins revealed by terahertz time-domain spectroscopy

Ohki Kambara1,2 and Keisuke Tominaga1

1Molecular Photoscience Research Center, Kobe University, Nada, Kobe, Japan
2Molecular Photoscience Research Center, Kobe University, Nada, Kobe 657-8501, Japan

Copyright © 2010 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We have measured spectra of the absorption coefficient and refractive index of hen egg white lysozyme in the wavenumber region from 7 cm–1 to 50 cm–1 by terahertz (THz) time-domain spectroscopy. From comparison with the results of the inelastic neutron scattering experiment it is concluded that analysis of the THz spectra provides information on the vibrational density of states. We studied temperature dependence of the THz spectra as well as hydration effect on them to discuss structural fluctuation of the protein. We observed dynamical transition at around 210 K for lysozyme.