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Updated: Jul 2, 2026

Biophysical Characterization of Flagellar Motor Functions
Published on: January 18, 2017
Fluctuation theorem and large deviation function for a solvable model of a molecular motor.
D Lacoste1, A W C Lau, K Mallick
1Laboratoire de Physico-Chimie Théorique, UMR 7083, ESPCI, 10 rue Vauquelin, 75231 Paris Cedex 05, France.
This study explores a minimal ratchet model for molecular motors, revealing how fluctuation theorems constrain their function far from equilibrium. Connections between different fluctuation theorem formulations are elucidated through entropy production.
Area of Science:
- Statistical Mechanics
- Non-equilibrium Thermodynamics
- Molecular Biophysics
Background:
- Molecular motors operate far from thermodynamic equilibrium.
- Fluctuation theorems provide fundamental insights into non-equilibrium systems.
- Previous work established a discrete stochastic model for molecular motors.
Purpose of the Study:
- To investigate constraints imposed by fluctuation theorems on molecular motor operation.
- To explore connections between different formulations of the fluctuation theorem.
- To unify these formulations under the concept of entropy production.
Main Methods:
- Analysis of a discrete stochastic minimal ratchet model.
- Exact calculation of the large deviation function for currents.
- Investigation of generating functions and probability ratios of velocities.
Main Results:
- Established connections between current generating functions, large deviation functions, and velocity probability ratios.
- Demonstrated the exact calculation of the large deviation function for the model.
- Showed that entropy production unifies different fluctuation theorem formulations.
Conclusions:
- The fluctuation theorem provides crucial constraints on molecular motor dynamics.
- Entropy production offers a unifying framework for understanding non-equilibrium statistical mechanics.
- This work deepens the theoretical understanding of molecular motors operating far from equilibrium.
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