1. Microbiology and Infectious Disease
  2. Structural Biology and Molecular Biophysics
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Structural analysis of the Legionella pneumophila Dot/Icm Type IV Secretion System Core Complex

  1. Clarissa L Durie
  2. Michael J Sheedlo
  3. Jeong Min Chung
  4. Brenda G Byrne
  5. Min Su
  6. Thomas Knight
  7. Michele Swanson  Is a corresponding author
  8. D Borden Lacy  Is a corresponding author
  9. Melanie D Ohi  Is a corresponding author
  1. University Of Michigan, United States
  2. Vanderbilt University Medical Center, United States
  3. University of Michigan, United States
Research Article
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Cite this article as: eLife 2020;9:e59530 doi: 10.7554/eLife.59530

Abstract

Legionella pneumophila is an opportunistic pathogen that causes the potentially fatal pneumonia Legionnaires' Disease. This infection and subsequent pathology require the Dot/Icm Type IV Secretion System (T4SS) to deliver effector proteins into host cells. Compared to prototypical T4SSs, the Dot/Icm assembly is much larger, containing ~27 different components including a core complex reported to be composed of five proteins: DotC, DotD, DotF, DotG, and DotH. Using single particle cryo-electron microscopy (cryo-EM), we report reconstructions of the core complex of the Dot/Icm T4SS that includes a symmetry mismatch between distinct structural features of the outer membrane cap (OMC) and periplasmic ring (PR). We present models of known core complex proteins, DotC, DotD, and DotH, and two structurally similar proteins within the core complex, DotK and Lpg0657. This analysis reveals the stoichiometry and contact interfaces between the key proteins of the Dot/Icm T4SS core complex and provides a framework for understanding a complex molecular machine.

Data availability

All cryo-EM data included in this manuscript are available through the Electron Microscopy Data Bank (EMD-22068, EMD-22069, EMD-22070 and EMD-22071). All models that were constructed from these data are available via the Protein Data Bank (PDB 6x62, 6x64, 6x65, and 6x66).

The following data sets were generated

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Author details

  1. Clarissa L Durie

    Life Sciences Institute, University Of Michigan, Ann Arbor, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-4027-4386
  2. Michael J Sheedlo

    Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-3185-1727
  3. Jeong Min Chung

    Life Sciences Institute, University of Michigan, Ann Arbor, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-4285-8764
  4. Brenda G Byrne

    Department of Microbiology & Immunology, University of Michigan, Ann Arbor, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Min Su

    Life Sciences Institute, University of Michigan, Ann Arbor, United States
    Competing interests
    The authors declare that no competing interests exist.
  6. Thomas Knight

    Department of Microbiology & Immunology, University of Michigan, Ann Arbor, United States
    Competing interests
    The authors declare that no competing interests exist.
  7. Michele Swanson

    Department of Microbiology & Immunology, University of Michigan, Ann Arbor, United States
    For correspondence
    mswanson@umich.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-2542-0266
  8. D Borden Lacy

    Pathology, Microbiology and Immunology; Biochemistry, Vanderbilt University Medical Center, Nashville, United States
    For correspondence
    borden.lacy@vanderbilt.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-2273-8121
  9. Melanie D Ohi

    Life Sciences Institute, University of Michigan, Ann Arbor, United States
    For correspondence
    mohi@umich.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-1750-4793

Funding

National Institute of Allergy and Infectious Diseases (F32 AI150027-01)

  • Clarissa L Durie

National Institute of General Medical Sciences (S10OD020011)

  • Melanie D Ohi

National Institute of Allergy and Infectious Diseases (2T32DK007673)

  • Michele Swanson

National Institute of Allergy and Infectious Diseases (R01AI118932)

  • Melanie D Ohi

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

Reviewing Editor

  1. Andrew P Carter, MRC Laboratory of Molecular Biology, United Kingdom

Publication history

  1. Received: June 1, 2020
  2. Accepted: September 1, 2020
  3. Accepted Manuscript published: September 2, 2020 (version 1)
  4. Version of Record published: September 23, 2020 (version 2)

Copyright

© 2020, Durie 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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