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A limiting speed for protein folding at low solvent viscosity
1Physics Department, University of Florida, P.O. Box 118440, Gainesville Florida 32611-8440, USA. sjhagen@ufl.edu
Journal of the American Chemical Society
|March 18, 2004
Summary
Protein folding speed is limited by internal friction, not just solvent viscosity. Even in low viscosity solvents, folding rate reaches a plateau, revealing a key factor in protein dynamics.
Area of Science:
- Biophysics
- Chemical Physics
- Molecular Biology
Background:
- Protein folding dynamics are often modeled using Kramers theory, which relates folding rate to friction.
- This friction is typically interpreted as solvent viscosity, suggesting faster folding in less viscous solutions.
Purpose of the Study:
- To investigate the theoretical limit of protein folding speed as solvent viscosity decreases.
- To determine if protein folding is solely dependent on solvent viscosity or if other factors play a role.
Main Methods:
- Theoretical analysis based on Kramers theory.
- Modeling protein folding dynamics under varying solvent viscosity conditions.
Main Results:
- Protein folding speed does not increase indefinitely with decreasing solvent viscosity.
- A finite folding speed limit is observed at low solvent viscosities.
- This limit suggests that internal friction within the protein becomes the rate-determining factor.
Conclusions:
- Protein folding is not solely governed by solvent viscosity.
- Internal friction plays a critical role in limiting folding speed, especially for fast-folding proteins.
- Understanding internal friction is crucial for predicting and controlling protein folding rates.