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Kinetic Asymmetry and Directionality of Nonequilibrium Molecular Systems
1Department of Physics and Astronomy, The University of Maine, 5709 Bennett Hall, Orono, ME-04469, USA.
Angewandte Chemie (International Ed. in English)
|January 18, 2024
Summary
Understanding molecular machines requires distinguishing between kinetic asymmetry and power strokes. Kinetic asymmetry dictates directionality in catalysis-driven machines, not power strokes, clarifying molecular machine function.
Area of Science:
- Chemistry
- Biophysics
- Nanotechnology
Background:
- Biomolecular machines are essential for life, processing energy and information.
- Synthetic molecular rotors, first reported in 1999, have seen significant design advancements.
- Confusion exists regarding fundamental principles for controlling molecular motion.
Purpose of the Study:
- To analyze the kinetics of molecular rotors and pumps thermodynamically.
- To clarify the roles of kinetic asymmetry and power strokes in molecular machine directionality.
- To reconcile mechanical and chemical descriptions of molecular machines.
Main Methods:
- Thermodynamically consistent kinetic analysis.
- Application of trajectory thermodynamics.
- Utilizing the nonequilibrium pump equality.
Main Results:
- Light-driven rotors operate via a power-stroke mechanism.
- Kinetic asymmetry solely determines directionality in catalysis-driven machines.
- Power strokes do not influence the directionality of catalysis-driven machines.
Conclusions:
- Kinetic asymmetry is the key determinant of directionality in many non-equilibrium chemical phenomena.
- This study clarifies fundamental principles for designing and controlling molecular machines.
- Distinguishes between energy barriers (kinetic asymmetry) and energy wells (power strokes) in molecular machines.
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