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Spatially Heterogeneous Surface Water Diffusivity around Structured Protein Surfaces at Equilibrium
Ryan Barnes1, Sheng Sun1, Yann Fichou1
1Department of Chemistry and Biochemistry, University of California, Santa Barbara , Santa Barbara, California 93106, United States.
Journal of the American Chemical Society
|November 2, 2017
Summary
Hydration water dynamics vary across protein surfaces, with hydrophobic regions showing slower water diffusion. This heterogeneity suggests proteins encode information in their hydration shells.
Area of Science:
- Biophysics
- Physical Chemistry
- Structural Biology
Background:
- Hydration water is crucial for protein-ligand interactions.
- Understanding water's role requires probing its dynamics on protein surfaces.
- Local variations in water properties are key to protein function.
Purpose of the Study:
- To investigate site-specific hydration water dynamics on a protein surface.
- To correlate water dynamics with local protein surface properties.
- To compare water dynamics across different biomolecular surfaces.
Main Methods:
- Overhauser dynamic nuclear polarization (ODNP) to probe water dynamics.
- Molecular dynamics (MD) simulations to determine protein surface hydropathy.
- Site-specific labeling for targeted measurements.
Main Results:
- Hydration water dynamics (diffusive water) are heterogeneous across the Chemotaxis Y (CheY) protein surface.
- Slower water diffusion correlates with more hydrophobic protein surface sites.
- Globular proteins exhibit more heterogeneous water dynamics than IDPs, peptides, and liposomes.
Conclusions:
- Protein surface structure dictates local hydration water dynamics.
- Structured proteins can encode information within their hydration shells.
- Hydration water heterogeneity is a fundamental aspect of protein biophysics.
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