4J32

Structure of the effector - immunity system Tae4 / Tai4 from Salmonella typhimurium


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.203 
  • R-Value Work: 0.182 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Structural Insights into the Effector - Immunity System Tae4/Tai4 from Salmonella typhimurium.

Benz, J.Reinstein, J.Meinhart, A.

(2013) Plos One 8: e67362-e67362

  • DOI: 10.1371/journal.pone.0067362
  • Primary Citation of Related Structures:  4J30

  • PubMed Abstract: 
  • Type-6-secretion systems of Gram-negative bacteria are widely distributed needle-like multi-protein complexes that are involved in microbial defense mechanisms. During bacterial competition these injection needles dispense effector proteins into the ...

    Type-6-secretion systems of Gram-negative bacteria are widely distributed needle-like multi-protein complexes that are involved in microbial defense mechanisms. During bacterial competition these injection needles dispense effector proteins into the periplasm of competing bacteria where they induce degradation of the peptidoglycan scaffold and lead to cell lysis. Donor cells co-produce immunity proteins and shuttle them into their own periplasm to prevent accidental toxication by siblings. Recently, a plethora of previously unidentified hydrolases have been suggested to be peptidoglycan degrading amidases. These hydrolases are part of effector/immunity pairs that have been associated with bacterial warfare by type-6-secretion systems. The Tae4 and Tai4 operon encoded by Salmonella typhimurium is one of these newly discovered effector/immunity pairs. The Tae4 effector proteins induce cell lysis by cleaving the γ-D-glutamyl-L-meso-diaminopimelic acid amide bond of acceptor stem muropeptides of the Gram-negative peptidoglycan. Although homologues of the Tae4/Tai4 system have been identified in various different pathogens, little is known about the functional mechanism of effector protein activity and their inhibition by the cognate immunity proteins. Here, we present the high-resolution crystal structure of the effector Tae4 of S. typhimurium in complex with its immunity protein Tai4. We show that Tae4 contains a classical NlpC/P60-peptidase core which is common to other effector proteins of the type-6-secretion system. However, Tae4 has unique structural features that are exclusively conserved within the family of Tae4 effectors and which are important for the substrate specificity. Most importantly, we show that although the overall structure of Tai4 is different to previously described immunity proteins, the essential mode of enzyme inhibition is conserved. Additionally, we provide evidence that inhibition in the Tae4/Tai4 heterotetramer relies on a central Tai4 dimer in order to acquire functionality.


    Organizational Affiliation

    Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Heidelberg, Germany.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Putative cytoplasmic protein
A
174Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720)N/A
Find proteins for Q93IS4 (Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720))
Go to UniProtKB:  Q93IS4
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Putative periplasmic protein
B
101Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720)N/A
Find proteins for Q8ZRL5 (Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720))
Go to UniProtKB:  Q8ZRL5
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
FLC
Query on FLC

Download SDF File 
Download CCD File 
A, B
CITRATE ANION
C6 H5 O7
KRKNYBCHXYNGOX-UHFFFAOYSA-K
 Ligand Interaction
ETX
Query on ETX

Download SDF File 
Download CCD File 
A, B
2-ETHOXYETHANOL
C4 H10 O2
ZNQVEEAIQZEUHB-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.203 
  • R-Value Work: 0.182 
  • Space Group: P 61 2 2
Unit Cell:
Length (Å)Angle (°)
a = 63.650α = 90.00
b = 63.650β = 90.00
c = 365.650γ = 120.00
Software Package:
Software NamePurpose
REFMACphasing
REFMACrefinement
XDSdata reduction
XSCALEdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-05-22
    Type: Initial release
  • Version 1.1: 2013-07-10
    Type: Database references
  • Version 1.2: 2014-01-15
    Type: Database references
  • Version 1.3: 2017-11-15
    Type: Refinement description