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High-Resolution Neutron Spectroscopy to Study Picosecond-Nanosecond Dynamics of Proteins and Hydration Water
Published on: April 28, 2022
The low-temperature dynamic crossover phenomenon in protein hydration water: simulations vs experiments
Marco Lagi1, Xiangqiang Chu, Chansoo Kim
1Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
The Journal of Physical Chemistry. B
|January 22, 2008
Summary
Researchers observed a dynamic crossover in lysozyme hydration water, revealing a shift from super-Arrhenius to Arrhenius behavior. This transition indicates a structural change in water from high-density to low-density liquid forms.
Area of Science:
- Physical Chemistry
- Biophysics
- Materials Science
Background:
- Water dynamics near biomolecules are crucial for biological function.
- Understanding hydration water structure and dynamics is key to protein function.
Purpose of the Study:
- To investigate the dynamic behavior of lysozyme hydration water.
- To identify phase transitions in hydration water structure.
Main Methods:
- Experimental techniques including neutron scattering and nuclear magnetic resonance.
- Molecular dynamics (MD) simulations using a realistic hydrated powder model and the TIP4P-Ew water model.
Main Results:
- Observed a super-Arrhenius-to-Arrhenius dynamic crossover in translational alpha-relaxation time and inverse self-diffusion constant.
- The crossover occurred in the temperature range of 223 ± 2 K for lysozyme hydration water.
- Convergence across experimental and simulation methods confirmed the findings.
Conclusions:
- The dynamic crossover is attributed to the structural evolution of hydration water.
- Water transitions from a high-density liquid to a low-density liquid form.
- This transition is linked to crossing the Widom line above water's potential liquid-liquid critical point.
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