5WEZ

Structure of the Tir-CesT effector-chaperone complex


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.74 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.211 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Molecular basis for CesT recognition of type III secretion effectors in enteropathogenic Escherichia coli.

Little, D.J.Coombes, B.K.

(2018) PLoS Pathog 14: e1007224-e1007224

  • DOI: 10.1371/journal.ppat.1007224
  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • Enteropathogenic Escherichia coli (EPEC) use a needle-like injection apparatus known as the type III secretion system (T3SS) to deliver protein effectors into host cells. Effector translocation is highly stratified in EPEC with the translocated intim ...

    Enteropathogenic Escherichia coli (EPEC) use a needle-like injection apparatus known as the type III secretion system (T3SS) to deliver protein effectors into host cells. Effector translocation is highly stratified in EPEC with the translocated intimin receptor (Tir) being the first effector delivered into the host. CesT is a multi-cargo chaperone that is required for the secretion of Tir and at least 9 other effectors. However, the structural and mechanistic basis for differential effector recognition by CesT remains unclear. Here, we delineated the minimal CesT-binding region on Tir to residues 35-77 and determined the 2.74 Å structure of CesT bound to an N-terminal fragment of Tir. Our structure revealed that the CesT-binding region in the N-terminus of Tir contains an additional conserved sequence, distinct from the known chaperone-binding β-motif, that we termed the CesT-extension motif because it extends the β-sheet core of CesT. This motif is also present in the C-terminus of Tir that we confirmed to be a unique second CesT-binding region. Point mutations that disrupt CesT-binding to the N- or C-terminus of Tir revealed that the newly identified carboxy-terminal CesT-binding region was required for efficient Tir translocation into HeLa cells and pedestal formation. Furthermore, the CesT-extension motif was identified in the N-terminal region of NleH1, NleH2, and EspZ, and mutations that disrupt this motif reduced translocation of these effectors, and in some cases, overall effector stability, thus validating the universality of this CesT-extension motif. The presence of two CesT-binding regions in Tir, along with the presence of the CesT-extension motif in other highly translocated effectors, may contribute to differential cargo recognition by CesT.


    Organizational Affiliation

    Department of Biochemistry & Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada.



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Tir chaperone
A
139Escherichia coli O127:H6 str. E2348/69Mutation(s): 0 
Gene Names: cesTE2348C_3940
Find proteins for P21244 (Escherichia coli O127:H6 (strain E2348/69 / EPEC))
Go to UniProtKB:  P21244
Protein Feature View
  • Reference Sequence

Find similar proteins by: Sequence  |  Structure

Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Translocated intimin receptor Tir
B
63Escherichia coli O127:H6 str. E2348/69Mutation(s): 0 
Gene Names: tirespEE2348C_3941
Find proteins for B7UM99 (Escherichia coli O127:H6 (strain E2348/69 / EPEC))
Go to UniProtKB:  B7UM99
Protein Feature View
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.74 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.211 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 66.96α = 90
b = 66.96β = 90
c = 75.71γ = 120
Software Package:
Software NamePurpose
PHENIXrefinement
iMOSFLMdata reduction
SCALAdata scaling
PHASERphasing

Structure Validation

View Full Validation Report



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Natural Sciences and Engineering Research Council Discovery GrantCanada341435-2010 RGPIN

Revision History 

  • Version 1.0: 2018-07-11
    Type: Initial release
  • Version 1.1: 2018-08-29
    Changes: Data collection, Database references