Crystal structure of enteropathogenic E.coli (EPEC) type III secretion system protein EscJ

Experimental Data Snapshot

  • Resolution: 1.80 Å
  • R-Value Free: 0.206 
  • R-Value Work: 0.184 
  • R-Value Observed: 0.185 

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Structural characterization of the molecular platform for type III secretion system assembly.

Yip, C.K.Kimbrough, T.G.Felise, H.B.Vuckovic, M.Thomas, N.A.Pfuetzner, R.A.Frey, E.A.Finlay, B.B.Miller, S.I.Strynadka, N.C.

(2005) Nature 435: 702-707

  • DOI: https://doi.org/10.1038/nature03554
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Type III secretion systems (TTSSs) are multi-protein macromolecular 'machines' that have a central function in the virulence of many Gram-negative pathogens by directly mediating the secretion and translocation of bacterial proteins (termed effectors) into the cytoplasm of eukaryotic cells. Most of the 20 unique structural components constituting this secretion apparatus are highly conserved among animal and plant pathogens and are also evolutionarily related to proteins in the flagellar-specific export system. Recent electron microscopy experiments have revealed the gross 'needle-shaped' morphology of the TTSS, yet a detailed understanding of the structural characteristics and organization of these protein components within the bacterial membranes is lacking. Here we report the 1.8-A crystal structure of EscJ from enteropathogenic Escherichia coli (EPEC), a member of the YscJ/PrgK family whose oligomerization represents one of the earliest events in TTSS assembly. Crystal packing analysis and molecular modelling indicate that EscJ could form a large 24-subunit 'ring' superstructure with extensive grooves, ridges and electrostatic features. Electron microscopy, labelling and mass spectrometry studies on the orthologous Salmonella typhimurium PrgK within the context of the assembled TTSS support the stoichiometry, membrane association and surface accessibility of the modelled ring. We propose that the YscJ/PrgK protein family functions as an essential molecular platform for TTSS assembly.

  • Organizational Affiliation

    Department of Biochemistry and Molecular Biology, University of British Columbia, 2146 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C, D
171Escherichia coliMutation(s): 3 
Gene Names: EscJ
Find proteins for Q8VQD3 (Escherichia coli)
Explore Q8VQD3 
Go to UniProtKB:  Q8VQD3
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8VQD3
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.80 Å
  • R-Value Free: 0.206 
  • R-Value Work: 0.184 
  • R-Value Observed: 0.185 
  • Space Group: P 65
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 164.817α = 90
b = 164.817β = 90
c = 67.179γ = 120
Software Package:
Software NamePurpose
SCALAdata scaling
CCP4data scaling
MOSFLMdata reduction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-06-07
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Non-polymer description, Version format compliance
  • Version 1.3: 2019-07-24
    Changes: Data collection, Refinement description
  • Version 1.4: 2021-10-20
    Changes: Database references, Derived calculations
  • Version 1.5: 2024-02-14
    Changes: Data collection