1. Is F-1-ATPase a Rotary Motor with Nearly 100% Efficiency? Quantitative Analysis of Chemomechanical Coupling and Mechanical Slip
- Author
-
Tomonari Sumi and Stefan Klumpp
- Subjects
Materials science ,ATPase ,Bioengineering ,02 engineering and technology ,Slip (materials science) ,Rotary engine ,rotary molecular motor ,Quantitative Biology::Cell Behavior ,Quantitative Biology::Subcellular Processes ,ATP hydrolysis ,F-ATPase ,Molecular motor ,Torque ,General Materials Science ,chemomechanical network model ,ATP synthesis ,Quantitative Biology::Biomolecules ,biology ,free-energy transduction efficiency ,Mechanical Engineering ,General Chemistry ,Mechanics ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Transduction (biophysics) ,torque-induced mechanical slip ,biology.protein ,F-1-ATPase ,0210 nano-technology - Abstract
We present a chemomechanical network model of the rotary molecular motor F1-ATPase which quantitatively describes not only the rotary motor dynamics driven by ATP hydrolysis but also the ATP synthesis caused by forced reverse rotations. We observe a high reversibility of F1-ATPase, that is, the main cycle of ATP synthesis corresponds to the reversal of the main cycle in the hydrolysis-driven motor rotation. However, our quantitative analysis indicates that torque-induced mechanical slip without chemomechanical coupling occurs under high external torque and reduces the maximal efficiency of the free energy transduction to 40–80% below the optimal efficiency. Heat irreversibly dissipates not only through the viscous friction of the probe but also directly from the motor due to torque-induced mechanical slip. Such irreversible heat dissipation is a crucial limitation for achieving a 100% free-energy transduction efficiency with biological nanomachines because biomolecules are easily deformed by external torque.
- Published
- 2019