Structural changes of keratin proteins under high pressure and heat

• Applicants: Professor Dr. Dan Eugen Demco; Professor Dr.-Ing. Crisan Popescu
• Subject Area: Biological and Biomimetic Chemistry
• Term: from 2007 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 43926214

• Final Report Year: 2011

Final Report Abstract

The main goal of this project is to characterize quantitatively the morphology, amino-acid side-chain dynamics, and domain sizes of α-keratins in the process of denaturation and chemical treatments. The water-protein interaction was also investigated for hard α-keratins. The methods used for this purpose were DSC, 1H, 13C, 129Xe solid-state NMR spectroscopy and 1H spin-diffusion with a new dipolar filter. The domain sizes were obtained by the solutions of the spin-diffusion equations for a cylindrical morphology. Moreover, a novel procedure was developed for evaluation of the domain size's in the initial rate approximation. The implications and mechanisms of α-keratin denaturation and the effect of water were discussed in the light of the new experimental data. The average orientation of the intermediate filaments in hard α-keratins was measured using angular dependence of the 1H line-width NMR spectra. All the phases show intermediate filament orientation with different contrast.

Publications

• Morphology and molecular mobility of fibrous hard α-keratins by 1H, 13C, and 129Xe NMR, J. Phys. Chem., 113(2009) 12136
  M. Baias, D.E. Demco, D. Istrate, C. Popescu, B. Blümich, M. Möller
  
• Morphology and side chain dynamics in hydrated hard α-keratin fibres by 1H solid-state NMR, Chem. Phys. Lett. 480 (2009) 300
  C. Melian, D. E. Demco, M. Istrate, A. Balaceanu, D. Moldovan, R. Fechete, C. Popescu, M. Möller
  
• Thermal denaturation of hydrated wool keratin by 1H solid-state NMR, J. Phys. Chem., 113, (2009)2184
  M. Baias, D.E. Demco, C. Popescu, R. Fechete, C. Melian, B. Blümich, M. Möller
  
• Morphology and molecular dynamics of hard alpha-keratin based micro-tubes by 1H and 13C solid-state NMR, Chem. Phys. Lett. 517(2011)86-91
  L. Utiu, D. E. Demco, R. Fechete, M. Möller, C. Popescu
  
• Morphology and molecular dynamics of hard α-keratin under pressure by 1H and 13C solid-state NMR, Chem. Phys. Lett. 509 (2011)62
  D.E. Demco, L. Utiu, W. Tillmann, B. Blümich, C. Popescu