18 May 2005 THz characterization of lysozyme at different conformations
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This work demonstrates application of Fourier Transform Infrared Spectroscopy (FTIR) technique in the low terahertz frequency range of 10-25 cm-1 to discriminate between different protein conformations and evaluate possible application of THz spectroscopy for monitoring of protein folding-unfolding process. A specific procedure developed earlier for unfolding lysozyme by salt (KSCN) precipitation and refolding the lysozyme molecules by removing of KSCN and dissolving in sodium acetate was used to prepare three different forms of lysozyme. In addition, two standard procedures were used to prepare samples in unfolded conformation: denaturation at high temperature ~95° C followed by fast freezing, and dissolution in 6 M guanidine. Thin, air dried protein films were characterized as well as material in the form of gel. Spectra reveal resonance features in transmission which represent vibrational modes in the protein samples. A great variability of spectral features for the different conformational states showed the sensitivity of vibrational frequencies to the three dimensional structure of proteins. The results obtained on liquid (gel) samples indicate that THz transmission spectroscopy can be used for monitoring folding-unfolding process in a realistic, aqueous environment.
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Tatiana Globus, Tatiana Globus, Tatyana Khromova, Tatyana Khromova, Rebecca Lobo, Rebecca Lobo, Dwight Woolard, Dwight Woolard, Nathan Swami, Nathan Swami, Erik Fernandez, Erik Fernandez, } "THz characterization of lysozyme at different conformations", Proc. SPIE 5790, Terahertz for Military and Security Applications III, (18 May 2005); doi: 10.1117/12.603581; https://doi.org/10.1117/12.603581


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