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The inverse relationship between protein dynamics and thermal stability.
A M Tsai1, T J Udovic, D A Neumann
1NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA. amos.tsai@nist.gov
Biophysical Journal
|September 22, 2001
Summary
Protein powders gain thermal stability when dehydrated or mixed with glassy compounds. Neutron scattering reveals that hydration introduces temperature-dependent relaxation dynamics in protein powders, influenced by additives like glycerol.
Area of Science:
- Biophysics
- Materials Science
- Protein Dynamics
Background:
- Protein powders are utilized in various applications, with thermal stability being a key factor.
- Dehydration and glassy compounds are known to enhance the thermal stability of proteins.
Purpose of the Study:
- To investigate the global dynamics of protein powders (lysozyme and ribonuclease A) using neutron scattering.
- To understand the impact of hydration and additives on protein dynamics and thermal stability.
Main Methods:
- Elastic and quasielastic neutron scattering measurements were performed on lysozyme and ribonuclease A powders.
- Analysis involved the Kohlrausch-Williams-Watts (KWW) formalism to characterize relaxation processes.
Main Results:
- In the absence of water, protein powders exhibited harmonic motions.
- Partial hydration induced temperature-dependent relaxational processes, indicated by quasielastic scattering.
- The KWW exponent (beta) decreased with increasing temperature, signifying emerging relaxation modes.
- Glycerol addition to lysozyme resulted in higher beta values compared to hydrated samples, indicating viscosity and stabilization.
Conclusions:
- Hydration significantly alters the dynamics of protein powders, introducing complex relaxation behaviors.
- The stabilizing effect of glycerol is linked to its viscosity and influence on protein relaxation dynamics.