Hydrostatic pressure response of α-keratin investigated with Raman spectroscopy
Year: 2025
Type: article
Abstract: Keratins represent an important class of sulfur-rich structural proteins. In this study, the pressure response of α-keratin, extracted from sheep wool, was investigated using Raman spectroscopy up to 4 GPa. A non-polar liquid (a Fluorinert™ FC70/77 mixture) served as the Pressure Transmitting Medium (PTM) in a Diamond Anvil Cell (DAC). Scanning Electron Microscopy (SEM) and Small-Angle X-ray Scattering (SAXS) were used for the morphological and structural characterization of the sample. Three Raman bands were monitored during compression and decompression: C H deformation, amide-I (dominated by the C O stretching vibration of the peptide bond) and C H stretching vibrations centered at approximately 1450, 1670 and 2940 cm −1 , respectively. The deformation modes of the C H bonds exhibited a weak positive pressure dependence (~1.7 cm −1 /GPa), whereas the corresponding stretching modes showed a much stronger dependence (6–9 cm −1 /GPa). A positive slope (~2.2 cm −1 /GPa) was also observed for the amide-I band, consistent with C O strengthening in the peptide bonds under compression. This behavior contrasts with that of collagen, which exhibits a negative pressure slope for the same vibrational mode. The opposite responses are discussed in relation to the different structural roles of hydrogen bonding in these two fibrous proteins. Overall, the response of keratin to high hydrostatic pressure is reversible.
Authors: A.M. Paschou, D. Christofilos, J. Arvanitidis, E. Pavlidou, I. Zizak, M. Katsikini
Language: English
Subfield: Biophysics
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $4,390
OpenAlex ID: W4413982192