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Updated: Feb 26, 2026
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Study of Protein Dynamics via Neutron Spin Echo Spectroscopy
Published on: April 13, 2022
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Functionally relevant protein dynamics monitored by time-resolved quasielastic neutron scattering.
Tatsiana Burankova1, Thomas Hauß2, Jacques Ollivier3
1Institute of Physics, University of Tartu, Tartu, Estonia; Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen PSI, Switzerland.
Biophysical Journal
|February 25, 2026
Summary
Protein dynamics are crucial for function. Light energy drives excess protein fluctuations in bacteriorhodopsin, directly promoting structural changes essential for its proton pump function.
Area of Science:
- Biophysics
- Structural Biology
- Enzyme Function
Background:
- Protein conformational flexibility is essential for function, but direct evidence is lacking.
- Previous studies inferred dynamics-function links indirectly through separate experiments.
Purpose of the Study:
- To directly investigate the real-time modulation of protein dynamics during the functional cycle.
- To examine the role of picosecond dynamics in the photocycle of bacteriorhodopsin (BR).
Main Methods:
- Time-resolved quasielastic neutron scattering (TR-QENS) with in-situ light excitation.
- Studied native purple membranes of bacteriorhodopsin at controlled hydration levels.
- Time-resolved absorption difference spectroscopy to monitor photocycle intermediates.
Main Results:
- Actinic light induced excess protein fluctuations within ~150 μs.
- These fluctuations decayed with a time constant of 250±50 μs.
- Decay correlated with the buildup of the M2 intermediate, indicating a role in global structural changes.
Conclusions:
- Excess protein fluctuations actively promote global structural changes in BR during its photocycle.
- Challenges the view of dynamics as mere "lubricating grease", suggesting an active role in energy conversion.
- Highlights the direct involvement of light-modulated protein dynamics in enzyme function.
