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Submillisecond Conformational Changes in Proteins Resolved by Photothermal Beam Deflection
Published on: February 18, 2014
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Protein-Bath Coupling of an Internal Reaction Coordinate at Intermediate Time Scales
Seung Jae Lee1,2, Saurabh Talele1,3, John T King1
1Center for Soft and Living Matter, Institute for Basic Science, Ulsan 44919, Republic of Korea.
The Journal of Physical Chemistry Letters
|November 4, 2021
Summary
This study reveals that internal protein reactions are influenced by solvent viscosity, deviating from standard models. Protein internal friction weakens this coupling at higher viscosities and intermediate timescales.
Area of Science:
- Biophysics
- Chemical Kinetics
- Protein Dynamics
Background:
- Protein reaction kinetics depend on protein-bath coupling.
- Large-scale motions are coupled; fast motions are uncoupled.
- Protein-bath coupling for internal, intermediate-timescale reactions is poorly understood.
Purpose of the Study:
- Investigate protein-bath coupling for internal reactions.
- Study the microsecond chemical reaction in eGFP's chromophore pocket.
- Analyze the influence of solvent viscosity on internal protein dynamics.
Main Methods:
- Single molecule 2D fluorescence lifetime correlation spectroscopy.
- Studied eGFP chromophore pocket reaction.
- Varied solvent viscosity.
Main Results:
- Observed coupling between internal chemical reaction and solvent viscosity.
- Deviation from Kramers' behavior noted.
- Internal friction identified as a factor weakening protein-solvent coupling.
Conclusions:
- Internal protein reactions are viscosity-dependent but deviate from Kramers' theory.
- Protein internal friction modulates protein-solvent coupling.
- This finding is relevant for understanding reactions within protein interiors.
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