Structural analysis of the legionella pneumophila dot/icm type iv secretion system core complex

Clarissa L. Durie, Michael J. Sheedlo, Jeong Min Chung, Brenda G. Byrne, Min Su, Thomas Knight, Michele Swanson, D. Borden Lacy, Melanie D. Ohi

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

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.

Original languageEnglish (US)
Article numbere59530
Pages (from-to)1-23
Number of pages23
JournaleLife
Volume9
DOIs
StatePublished - Sep 2020
Externally publishedYes

Bibliographical note

Funding Information:
The work presented here was supported by NIH R01AI118932 (MDO), F32 AI150027-01 (CLD), NIH 2T32DK007673 (MJS), S10OD020011 and the University of Michigan Department of Microbiology and Immunology (Swanson). Some of this work was performed at the National Center for CryoEM Access and Training (NCCAT) and the Simons Electron Microscopy Center located at the New York Structural Biology Center, supported by the NIH Common Fund Transformative High Resolution Cryo-Electron Microscopy program (U24 GM129539,) and by grants from the Simons Foundation (SF349247) and NY State. A portion of the molecular graphics and analyses was performed with UCSF Chimera, developed by the Resource for Biocomputing, Visualization, and Informatics at UC-San Francisco, with support from NIH P41-GM103311. Mass spectrometry experiments were performed by the University of Michigan Proteomics Resource Facility. The authors acknowledge Young-In (Eva) Kwon for assistance with figures. We thank the Cianfrocco, Cover, Lacy, and Ohi labs for helpful discussions. We acknowledge the use of the U-M LSI cryo-EM facility, managed by M Su, A Bondy, and L Koepping, and U-M LSI IT support. We thank U-M BSI and LSI for significant support of the cryo-EM facility. 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.

Funding Information:
The work presented here was supported by NIH R01AI118932 (MDO), F32 AI150027-01 (CLD), NIH 2T32DK007673 (MJS), S10OD020011 and the University of Michigan Department of Microbiology and Immunology (Swanson). Some of this work was performed at the National Center for CryoEM Access and Training (NCCAT) and the Simons Electron Microscopy Center located at the New York Structural Biology Center, supported by the NIH Common Fund Transformative High Resolution Cryo-Electron Microscopy program (U24 GM129539,) and by grants from the Simons Foundation (SF349247) and NY State. A portion of the molecular graphics and analyses was performed with UCSF Chimera, developed by the Resource for Biocomputing, Visualization, and Informatics at UC-San Francisco, with support from NIH P41-GM103311. Mass spectrometry experiments were performed by the University of Michigan Proteomics Resource Facility. The authors acknowledge Young-In (Eva) Kwon for assistance with figures. We thank the Cianfrocco, Cover, Lacy, and Ohi labs for helpful discussions. We acknowledge the use of the U-M LSI cryo-EM facility, managed by M Su, A Bondy, and L Koepping, and U-M LSI IT support. We thank U-M BSI and LSI for significant support of the cryo-EM facility.

Publisher Copyright:
© Durie et al.

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