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Updated: May 27, 2026
08:48
High-Resolution Neutron Spectroscopy to Study Picosecond-Nanosecond Dynamics of Proteins and Hydration Water
Published on: April 28, 2022
More than one dynamic crossover in protein hydration water
Marco G Mazza1, Kevin Stokely, Sara E Pagnotta
1Center for Polymer Studies and Department of Physics, Boston University, Boston, MA 02215, USA. mgmazza@mail.tu-berlin.de
Summary
Protein hydration water exhibits unique dynamics, with two distinct temperature-induced transitions observed in its hydrogen bond network. These findings offer insights into water
Area of Science:
- Physical Chemistry
- Biophysics
- Materials Science
Background:
- Liquid water's behavior in the supercooled region is crucial for understanding its structure and dynamics.
- Unlike bulk water, protein hydration water does not freeze due to its interaction with proteins.
- The hydrogen bond (HB) network dynamics of water adsorbed on protein surfaces are not fully understood.
Purpose of the Study:
- To investigate the dynamics of the hydrogen bond (HB) network in protein hydration water.
- To compare experimental measurements with a coarse-grained model of hydration water.
- To identify dynamic transitions and their origins in the HB network of water molecules interacting with a globular protein.
Main Methods:
- Dielectric spectroscopy was used to measure the temperature dependence of relaxation times for proton charge fluctuations.
- Monte Carlo simulations and mean-field calculations were employed to study the dynamics and thermodynamics of a coarse-grained water model.
- Experimental data from a hydrated globular protein were compared with simulation results.
Main Results:
- Both experimental and model analyses revealed two dynamic crossovers at approximately 252 K and 181 K.
- These crossovers correlate with two specific heat maxima at ambient pressure.
- The first crossover is linked to fluctuations in hydrogen bond formation, and the second to cooperative reordering of the HB network.
Conclusions:
- The study successfully characterized two distinct dynamic transitions in protein hydration water.
- Experimental findings align with a coarse-grained model, validating its ability to reproduce hydration water properties.
- The identified crossovers provide a deeper understanding of water's behavior at the nanoscale, particularly its hydrogen bond network dynamics under confinement.
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