Is F 1 -ATPase a Rotary Motor with Nearly 100% Efficiency? Quantitative Analysis of Chemomechanical Coupling and Mechanical Slip

Tomonari Sumi, Stefan Klumpp

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We present a chemomechanical network model of the rotary molecular motor F 1 -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 F 1 -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.

Original languageEnglish
Pages (from-to)3370-3378
Number of pages9
JournalNano Letters
Volume19
Issue number5
DOIs
Publication statusPublished - May 8 2019

Keywords

  • ATP synthesis
  • F -ATPase
  • chemomechanical network model
  • free-energy transduction efficiency
  • rotary molecular motor
  • torque-induced mechanical slip

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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