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Updated: Jun 12, 2026
08:28
Measurement of Force-Sensitive Protein Dynamics in Living Cells Using a Combination of Fluorescent Techniques
Published on: November 2, 2018
Collapse dynamics of single proteins extended by force.
Ronen Berkovich1, Sergi Garcia-Manyes, Michael Urbakh
1School of Chemistry, Tel Aviv University, Tel Aviv, Israel.
Biophysical Journal
|June 2, 2010
Summary
Single-molecule force spectroscopy reveals complex protein folding pathways beyond simple two-state models. A new model explains variable collapse trajectories using entropic elasticity and hydrophobic interactions, validated by experiments.
Area of Science:
- Biophysics
- Protein dynamics
- Single-molecule studies
Background:
- Single-molecule force spectroscopy (SMFS) offers novel insights into protein dynamics.
- Protein folding observed via SMFS can deviate from bulk measurements, showing complex collapse trajectories.
Purpose of the Study:
- To develop a model explaining the variable collapse trajectories observed during protein folding after force quench.
- To validate the force-clamp technique for mapping protein free-energy landscapes.
Main Methods:
- Modeling protein free energy as a sum of entropic elasticity and hydrophobic interactions.
- Solving the Langevin equation to simulate protein folding trajectories under force quench conditions.
Main Results:
- A force-dependent energy barrier model was developed, vanishing at a critical force (Fc).
- Simulated folding trajectories accurately reproduced experimentally observed stages and kinetics for ubiquitin and I27.
- The model successfully explains deviations from two-state folding behavior.
Conclusions:
- The developed model provides a mechanistic understanding of complex protein folding pathways.
- SMFS and the force-clamp technique are powerful tools for characterizing protein free-energy landscapes from extended states.
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