Study of solvent-protein coupling effects by neutron scattering

Area of Science:

• Biophysics
• Materials Science
• Physical Chemistry

Background:

• Proteins are crucial biological molecules whose function depends on their dynamics.
• Bio-preserving agents like glycerol and disaccharides are used to stabilize proteins.
• Understanding protein-solvent interactions is key to improving preservation techniques.

Purpose of the Study:

• To characterize the dynamical behavior of the protein dUTPase in glycerol and disaccharide solutions.
• To investigate the effect of bio-preserving agents on water dynamics.
• To explore the relationship between protein dynamics and the surrounding matrix dynamics.

Main Methods:

• Elastic incoherent neutron scattering (EINS) to probe dynamics.
• Analysis of mean square displacement (MSD) to define kinetic fragility.
• Comparative study using glycerol, trehalose, maltose, and sucrose as solvents.

Main Results:

• Disaccharides significantly slow down water dynamics, with trehalose exhibiting the strongest effect.
• Kinetic fragility of the medium was characterized using MSD, correlating with viscosity-based fragility.
• Protein dynamics were found to be coupled with the dynamics of the surrounding bio-preserving matrix.

Conclusions:

• Trehalose, maltose, and sucrose effectively modulate water dynamics, impacting protein environments.
• The study provides a method to characterize medium fragility using neutron scattering.
• Protein dynamics are intrinsically linked to the dynamics of their bio-preserving liquid or glassy environment.