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 

wwPDB Validation 3D Report Full Report


This is version 1.3 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.USA 111: 14758-14763

  • DOI: 10.1073/pnas.1409345111
  • Primary Citation of Related Structures:  

  • 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 infect ...

    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: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
ESX-3 secretion-associated protein EspG3
A
311Mycobacterium tuberculosis (strain CDC 1551 / Oshkosh)Mutation(s): 0 
Gene Names: espG3
Find proteins for P9WJC6 (Mycobacterium tuberculosis (strain CDC 1551 / Oshkosh))
Go to UniProtKB:  P9WJC6
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.85 Å
  • R-Value Free: 0.274 
  • R-Value Work: 0.225 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 74.980α = 90.00
b = 96.310β = 90.00
c = 94.450γ = 90.00
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
PHASERphasing
Blu-Icedata collection

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute Of Allergy and Infectious DiseasesUnited StatesR01AI081727
Damon Runyon Cancer Research FoundationUnited StatesDRG-2140-12

Revision History 

  • Version 1.0: 2014-10-01
    Type: Initial release
  • Version 1.1: 2014-10-15
    Type: Database references
  • Version 1.2: 2014-10-29
    Type: Database references
  • Version 1.3: 2017-09-27
    Type: Author supporting evidence, Database references, Derived calculations, Other, Refinement description, Source and taxonomy, Structure summary