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 journalArticlepeer-review

    4 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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