Probing Protein Dynamics Using Multifield Variable Temperature NMR Relaxation and Molecular Dynamics Simulation.

Area of Science:

• Physical biology
• Biophysics
• Protein dynamics

Background:

• Understanding protein dynamics is crucial for deciphering protein function.
• Previous methods allowed measurement of distinct dynamic modes but required further validation.
• Solid-state nuclear magnetic resonance (ssNMR) relaxation is a powerful tool for probing molecular motion.

Purpose of the Study:

• To extend ssNMR relaxation measurements to multiple magnetic field strengths.
• To refine motional models and assess the robustness of the technique.
• To investigate the physical basis of protein dynamics.

Main Methods:

• Variable temperature solid-state nuclear magnetic resonance (ssNMR) relaxation measurements.
• Measurements performed at multiple magnetic field strengths.
• Comparison with variable temperature molecular dynamics simulations.

Main Results:

• Simultaneous measurement of multiple activation energies for distinct dynamic modes in protein GB1.
• Identification of backbone and side-chain motions with low- (approx. 5 kJ·mol⁻¹) and high- (approx. 25 kJ·mol⁻¹) energy modes.
• Validation of the ssNMR relaxation method through comparison with molecular dynamics simulations.

Conclusions:

• The extended ssNMR relaxation approach provides robust characterization of protein dynamics.
• The method successfully distinguishes between different energy modes of protein motion.
• Results support the interpretation of experimental data in terms of molecular motion, enhancing our understanding of protein dynamics.