Crystal structure of T6SS SciP/TssL from Escherichia Coli Enteroaggregative 042

Experimental Data Snapshot

  • Resolution: 2.63 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.235 
  • R-Value Observed: 0.237 

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Structural characterization and oligomerization of the TssL protein, a component shared by bacterial type VI and type IVb secretion systems.

Durand, E.Zoued, A.Spinelli, S.Watson, P.J.Aschtgen, M.S.Journet, L.Cambillau, C.Cascales, E.

(2012) J Biol Chem 287: 14157-14168

  • DOI: https://doi.org/10.1074/jbc.M111.338731
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The Type VI secretion system (T6SS) is a macromolecular system distributed in Gram-negative bacteria, responsible for the secretion of effector proteins into target cells. The T6SS has a broad versatility as it can target both eukaryotic and prokaryotic cells. It is therefore involved in host pathogenesis or killing neighboring bacterial cells to colonize a new niche. At the architecture level, the T6SS core apparatus is composed of 13 proteins, which assemble in two subcomplexes. One of these subcomplexes, composed of subunits that share structural similarities with bacteriophage tail and baseplate components, is anchored to the cell envelope by the membrane subcomplex. This latter is constituted of at least three proteins, TssL, TssM, and TssJ. The crystal structure of the TssJ outer membrane lipoprotein and its interaction with the inner membrane TssM protein have been recently reported. TssL and TssM share sequence homology and characteristics with two components of the Type IVb secretion system (T4bSS), IcmH/DotU and IcmF, respectively. In this study, we report the crystal structure of the cytoplasmic domain of the TssL inner membrane protein from the enteroaggregative Escherichia coli Sci-1 T6SS. It folds as a hook-like structure composed of two three-helix bundles. Two TssL molecules associate to form a functional complex. Although the TssL trans-membrane segment is the main determinant of self-interaction, contacts between the cytoplasmic domains are required for TssL function. Based on sequence homology and secondary structure prediction, we propose that the TssL structure is the prototype for the members of the TssL and IcmH/DotU families.

  • Organizational Affiliation

    Aix-Marseille Université, Architecture et Fonction des Macromolécules Biologiques, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Putative type VI secretion protein183Escherichia coli 042Mutation(s): 0 
Gene Names: EC042_4527SciP/TssL
Find proteins for D3GU40 (Escherichia coli O44:H18 (strain 042 / EAEC))
Explore D3GU40 
Go to UniProtKB:  D3GU40
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupD3GU40
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on GOL

Download Ideal Coordinates CCD File 
C3 H8 O3
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
Query on MSE
Experimental Data & Validation

Experimental Data

  • Resolution: 2.63 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.235 
  • R-Value Observed: 0.237 
  • Space Group: I 2 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 51.61α = 90
b = 82.03β = 90
c = 96.08γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-03-07
    Type: Initial release
  • Version 1.1: 2013-01-09
    Changes: Database references
  • Version 1.2: 2017-11-08
    Changes: Refinement description