1. Biochemistry and Chemical Biology
  2. Structural Biology and Molecular Biophysics
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Resolving dual binding conformations of cellulosome cohesin-dockerin complexes using single-molecule force spectroscopy

  1. Markus A Jobst
  2. Lukas F Milles
  3. Constantin Schoeler
  4. Wolfgang Ott
  5. Daniel B Fried
  6. Edward A Bayer
  7. Hermann E Gaub
  8. Michael A Nash  Is a corresponding author
  1. Ludwig-Maximilians-Universität München, Germany
  2. Kean University, United States
  3. Weizmann Institute of Science, Israel
Research Article
  • Cited 29
  • Views 1,361
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Cite this article as: eLife 2015;4:e10319 doi: 10.7554/eLife.10319

Abstract

Receptor-ligand pairs are ordinarily thought to interact through a lock and key mechanism, where a unique molecular conformation is formed upon binding. Contrary to this paradigm, cellulosomal cohesin-dockerin (Coh-Doc) pairs are believed to interact through redundant dual binding modes consisting of two distinct conformations. Here, we combined site-directed mutagenesis and single-molecule force spectroscopy (SMFS) to study the unbinding of Coh:Doc complexes under force. We designed Doc mutations to knock out each binding mode, and compared their single-molecule unfolding patterns as they were dissociated from Coh using an atomic force microscope (AFM) cantilever. Although average bulk measurements were unable to resolve the differences in Doc binding modes due to the similarity of the interactions, with a single-molecule method we were able to discriminate the two modes based on distinct differences in their mechanical properties. We conclude that wild-type Doc from Clostridium thermocellum exocellulase Cel48S populates each binding mode with equal probability.

Article and author information

Author details

  1. Markus A Jobst

    Lehrstuhl für Angewandte Physik, Center for Nanoscience, Ludwig-Maximilians-Universität München, Munich, Germany
    Competing interests
    The authors declare that no competing interests exist.
  2. Lukas F Milles

    Lehrstuhl für Angewandte Physik, Center for Nanoscience, Ludwig-Maximilians-Universität München, Munich, Germany
    Competing interests
    The authors declare that no competing interests exist.
  3. Constantin Schoeler

    Lehrstuhl für Angewandte Physik, Center for Nanoscience, Ludwig-Maximilians-Universität München, Munich, Germany
    Competing interests
    The authors declare that no competing interests exist.
  4. Wolfgang Ott

    Lehrstuhl für Angewandte Physik, Center for Nanoscience, Ludwig-Maximilians-Universität München, Munich, Germany
    Competing interests
    The authors declare that no competing interests exist.
  5. Daniel B Fried

    Kean University, Union, United States
    Competing interests
    The authors declare that no competing interests exist.
  6. Edward A Bayer

    Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
    Competing interests
    The authors declare that no competing interests exist.
  7. Hermann E Gaub

    Lehrstuhl für Angewandte Physik, Center for Nanoscience, Ludwig-Maximilians-Universität München, Munich, Germany
    Competing interests
    The authors declare that no competing interests exist.
  8. Michael A Nash

    Lehrstuhl für Angewandte Physik, Center for Nanoscience, Ludwig-Maximilians-Universität München, Munich, Germany
    For correspondence
    michael.nash@lmu.de
    Competing interests
    The authors declare that no competing interests exist.

Reviewing Editor

  1. Taekjip Ha, Johns Hopkins University School of Medicine

Publication history

  1. Received: July 23, 2015
  2. Accepted: October 28, 2015
  3. Accepted Manuscript published: October 31, 2015 (version 1)
  4. Version of Record published: January 7, 2016 (version 2)

Copyright

© 2015, Jobst 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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