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Dynamical Transition in Dehydrated Proteins.

Accepted version
Peer-reviewed

Type

Article

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Authors

Kölbel, Johanna 
Anuschek, Moritz L 
Stelzl, Ivonne 
Santitewagun, Supawan 
Friess, Wolfgang 

Abstract

Terahertz time-domain spectroscopy and differential scanning calorimetry were used to study the role of the dynamics of biomolecules decoupled from solvent effects. Lyophilized sucrose exhibited steadily increasing absorption with temperature as anharmonic excitations commenced as the system emerged from a deep minimum of the potential energy landscape where harmonic vibrations dominate. The polypeptide bacitracin and two globular proteins, lysozyme and human serum albumin, showed a more complex temperature dependence. Further analysis focused on the spectral signature below and above the boson peak. We found evidence of the onset of anharmonic motions that are characteristic for partial unfolding and molecular jamming in the dry biomolecules. The activation of modes of the protein molecules at temperatures comparable to the protein dynamical transition temperature was observed in the absence of hydration. No evidence of Fröhlich coherence, postulated to facilitate biological function, was found in our experiments.

Description

Keywords

34 Chemical Sciences

Journal Title

J Phys Chem Lett

Conference Name

Journal ISSN

1948-7185
1948-7185

Volume Title

Publisher

American Chemical Society (ACS)
Sponsorship
EPSRC (EP/S023046/1)
Engineering and Physical Sciences Research Council (EP/L015889/1)