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A broad glass transition in hydrated proteins
S Khodadadi1, A Malkovskiy, A Kisliuk
1Department of Polymer Science, University of Akron, Akron, OH 44325, USA.
Biochimica Et Biophysica Acta
|June 23, 2009
Summary
Raman and Brillouin scattering reveal a broad glass transition temperature (Tg) of approximately 180 K in hydrated lysozyme. This highlights distinct behavior in biomolecules compared to simple glasses, with the underlying structural relaxation remaining unclear.
Area of Science:
- Biophysics
- Materials Science
- Physical Chemistry
Background:
- Proteins in hydrated states exhibit complex dynamics relevant to biological function.
- Understanding the glass transition temperature (Tg) in biomolecules is crucial for their stability and behavior.
- Hydrated protein systems differ significantly from simple glass-forming liquids.
Purpose of the Study:
- To determine the glass transition temperature (Tg) of hydrated proteins using spectroscopic methods.
- To investigate the nature of the glass transition in hydrated lysozyme.
- To differentiate the glass transition from the dynamic transition in biomolecular systems.
Main Methods:
- Raman scattering spectroscopy.
- Brillouin scattering spectroscopy.
- Analysis of glass transition phenomena in hydrated lysozyme.
Main Results:
- A broad glass transition was observed in hydrated lysozyme with Tg approximately 180+/-15 K.
- The determined Tg aligns with literature values for hydrated globular proteins (160-200 K).
- The primary structural relaxation mechanism responsible for freezing at Tg remains unidentified.
Conclusions:
- Hydrated proteins display a distinct glass transition behavior compared to simple glass formers.
- The glass transition (Tg) at ~180 K should not be confused with the dynamic transition (TD) at ~200-230 K.
- Further research is needed to elucidate the structural relaxation dynamics in hydrated protein systems.
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