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Hydrostatic pressure response of α-keratin investigated with Raman spectroscopy
A M Paschou1, D Christofilos2, J Arvanitidis1
1School of Physics, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece.
International Journal of Biological Macromolecules
|September 6, 2025
Summary
High hydrostatic pressure reversibly alters alpha-keratin structure, as shown by Raman spectroscopy. This protein
Area of Science:
- Biophysics
- Materials Science
- Spectroscopy
Background:
- Keratins are essential sulfur-rich structural proteins found in various biological tissues.
- Understanding protein behavior under extreme conditions is crucial for diverse scientific applications.
Purpose of the Study:
- To investigate the pressure-induced structural changes in alpha-keratin from sheep wool.
- To analyze the reversible response of keratin to high hydrostatic pressure using Raman spectroscopy.
Main Methods:
- High-pressure Raman spectroscopy up to 4 GPa using a Diamond Anvil Cell (DAC).
- Morphological and structural characterization via Scanning Electron Microscopy (SEM) and Small-Angle X-ray Scattering (SAXS).
- Monitoring of CH deformation, amide-I, and CH stretching Raman bands.
Main Results:
- CH deformation and stretching modes showed positive pressure dependence, with stretching modes exhibiting a stronger response.
- The amide-I band (peptide bond) displayed a positive pressure slope, indicating CO bond strengthening.
- Keratin's response to pressure was found to be reversible, contrasting with collagen's behavior.
Conclusions:
- Alpha-keratin exhibits distinct pressure-dependent vibrational changes, particularly in peptide bonds.
- The structural role of hydrogen bonding differs significantly between keratin and collagen under pressure.
- Keratin demonstrates remarkable structural resilience and reversibility under high hydrostatic pressure.
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