4W4I

Crystal structure of EspG3 from the ESX-3 type VII secretion system of M. tuberculosis


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.85 Å
  • R-Value Free: 0.274 
  • R-Value Work: 0.225 
  • R-Value Observed: 0.230 

wwPDB Validation   3D Report Full Report


This is version 1.5 of the entry. See complete history


Literature

Structure of a PE-PPE-EspG complex from Mycobacterium tuberculosis reveals molecular specificity of ESX protein secretion.

Ekiert, D.C.Cox, J.S.

(2014) Proc Natl Acad Sci U S A 111: 14758-14763

  • DOI: https://doi.org/10.1073/pnas.1409345111
  • Primary Citation of Related Structures:  
    4W4I, 4W4J, 4W4K, 4W4L

  • PubMed Abstract: 

    Nearly 10% of the coding capacity of the Mycobacterium tuberculosis genome is devoted to two highly expanded and enigmatic protein families called PE and PPE, some of which are important virulence/immunogenicity factors and are secreted during infection via a unique alternative secretory system termed "type VII." How PE-PPE proteins function during infection and how they are translocated to the bacterial surface through the five distinct type VII secretion systems [ESAT-6 secretion system (ESX)] of M. tuberculosis is poorly understood. Here, we report the crystal structure of a PE-PPE heterodimer bound to ESX secretion-associated protein G (EspG), which adopts a novel fold. This PE-PPE-EspG complex, along with structures of two additional EspGs, suggests that EspG acts as an adaptor that recognizes specific PE-PPE protein complexes via extensive interactions with PPE domains, and delivers them to ESX machinery for secretion. Surprisingly, secretion of most PE-PPE proteins in M. tuberculosis is likely mediated by EspG from the ESX-5 system, underscoring the importance of ESX-5 in mycobacterial pathogenesis. Moreover, our results indicate that PE-PPE domains function as cis-acting targeting sequences that are read out by EspGs, revealing the molecular specificity for secretion through distinct ESX pathways.


  • Organizational Affiliation

    Department of Microbiology and Immunology, University of California, San Francisco, CA 94143 damian.ekiert@ucsf.edu jeffery.cox@ucsf.edu.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
ESX-3 secretion-associated protein EspG3311Mycobacterium tuberculosis str. Erdman = ATCC 35801Mutation(s): 0 
Gene Names: ERDMAN_0323Q643_00302
UniProt
Find proteins for P9WJC6 (Mycobacterium tuberculosis (strain CDC 1551 / Oshkosh))
Explore P9WJC6 
Go to UniProtKB:  P9WJC6
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP9WJC6
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download Ideal Coordinates CCD File 
B [auth A]SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.85 Å
  • R-Value Free: 0.274 
  • R-Value Work: 0.225 
  • R-Value Observed: 0.230 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 74.98α = 90
b = 96.31β = 90
c = 94.45γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
Blu-Icedata collection
XDSdata reduction
PHASERphasing

Structure Validation

View Full Validation Report



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)United StatesR01AI081727
Damon Runyon Cancer Research FoundationUnited StatesDRG-2140-12

Revision History  (Full details and data files)

  • Version 1.0: 2014-10-01
    Type: Initial release
  • Version 1.1: 2014-10-15
    Changes: Database references
  • Version 1.2: 2014-10-29
    Changes: Database references
  • Version 1.3: 2017-09-27
    Changes: Author supporting evidence, Database references, Derived calculations, Other, Refinement description, Source and taxonomy, Structure summary
  • Version 1.4: 2019-12-11
    Changes: Author supporting evidence
  • Version 1.5: 2023-09-27
    Changes: Data collection, Database references, Refinement description