A single power stroke by ATP binding drives substrate translocation in a heterodimeric ABC transporter

  1. Erich Stefan
  2. Susanne Hofmann
  3. Robert Tampé  Is a corresponding author
  1. Goethe-University Frankfurt, Germany

Abstract

ATP-binding cassette (ABC) transporters constitute the largest family of primary active transporters, responsible for many physiological processes and human maladies. However, the mechanism how chemical energy of ATP facilitates translocation of chemically diverse compounds across membranes is poorly understood. Here, we advance the quantitative mechanistic understanding of the heterodimeric ABC transporter TmrAB, a functional homolog of the transporter associated with antigen processing (TAP) by single-turnover analyses at single-liposome resolution. We reveal that a single conformational switch by ATP binding drives unidirectional substrate translocation. After this power stroke, ATP hydrolysis and phosphate release launch the return to the resting state, which facilitates nucleotide exchange and a new round of substrate binding and translocation. In contrast to hitherto existing steady-state assays, our single-turnover approach uncovers the power stroke in substrate translocation and the tight chemomechanical coupling in these molecular machines.

Data availability

All data generated or analysed during this study are included in the manuscript and supporting files. Source data files have been provided for Figures 1, 2, 3, 4, and 5.

Article and author information

Author details

  1. Erich Stefan

    Institute of Biochemistry, Biocenter, Goethe-University Frankfurt, Frankfurt, Germany
    Competing interests
    The authors declare that no competing interests exist.
  2. Susanne Hofmann

    Institute of Biochemistry, Biocenter, Goethe-University Frankfurt, Frankfurt, Germany
    Competing interests
    The authors declare that no competing interests exist.
  3. Robert Tampé

    Institute of Biochemistry, Biocenter, Goethe-University Frankfurt, Frankfurt, Germany
    For correspondence
    tampe@em.uni-frankfurt.de
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-0403-2160

Funding

Deutsche Forschungsgemeinschaft (SFB 807 and Ta157/12-1)

  • Robert Tampé

European Commission (ERC_Ad 789121)

  • Robert Tampé

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Sonja V Albers, University of Freiburg, Germany

Publication history

  1. Received: February 11, 2020
  2. Accepted: April 20, 2020
  3. Accepted Manuscript published: April 21, 2020 (version 1)
  4. Version of Record published: May 7, 2020 (version 2)

Copyright

© 2020, Stefan et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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  1. Erich Stefan
  2. Susanne Hofmann
  3. Robert Tampé
(2020)
A single power stroke by ATP binding drives substrate translocation in a heterodimeric ABC transporter
eLife 9:e55943.
https://doi.org/10.7554/eLife.55943

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