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Torsional elasticity and energetics of F1-ATPase

Abstract

FoF1-ATPase is a rotary motor protein synthesizing ATP from ADP driven by a cross-membrane proton gradient. The proton flow through the membrane-embedded Fo generates the rotary torque that drives the rotation of the asymmetric shaft of F1. Mechanical energy of the rotating shaft is used by the F1 catalytic subunit to synthesize ATP. It was suggested that elastic power transmission with transient storage of energy in some compliant part of the shaft is required for the observed high turnover rate. We used atomistic simulations to study the spatial distribution and structural determinants of the F1 torsional elasticity at the molecular level and to comprehensively characterize the elastic properties of F1-ATPase. Our fluctuation analysis revealed an unexpected heterogeneity of the F1 shaft elasticity. Further, we found that the measured overall torsional moduli of the shaft arise from two distinct contributions, the intrinsic elasticity and the effective potential imposed on the shaft by the catalytic subunit. Separation of these two contributions provided a quantitative description of the coupling between the rotor and the catalytic subunit. This description enabled us to propose a minimal quantitative model of the F1 energetics along the rotary degrees of freedom near the resting state observed in the crystal structures. As opposed to the usually employed models where the motor mechanical progression is described by a single angular variable, our multidimensional treatment incorporates the spatially inhomogeneous nature of the shaft and its interactions with the stator and offers new insight into the mechanoenzymatics of F1-ATPase.

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Authors (2)

  • Photo of prof. dr hab. inż. Jacek Czub

    Jacek Czub prof. dr hab. inż.

    • Max Planck Institute for Biophysical Chemistry Dept. Theoretical and Computational Biophysics
  • Photo of  Helmut Grubmueller

    Helmut Grubmueller

    • Max Planck Institute for Biophysical Chemistry Dept. Theoretical and Computational Biophysics

Keywords

Details

Category:
Articles
Type:
artykuł w czasopiśmie wyróżnionym w JCR
Published in:
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA no. 108, edition 18, pages 7408 - 7413,
ISSN: 0027-8424
Language:
English
Publication year:
2011
Bibliographic description:
Czub J., Grubmueller H.: Torsional elasticity and energetics of F1-ATPase// PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA. -Vol. 108, iss. 18 (2011), s.7408-7413
DOI:
Digital Object Identifier (open in new tab) 10.1073/pnas.1018686108
Verified by:
Gdańsk University of Technology

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