Structural characterization of a secretin pilot protein from the type III secretion system (T3SS) of Pseudomonas aeruginosa

Experimental Data Snapshot

  • Resolution: 1.81 Å
  • R-Value Free: 0.262 
  • R-Value Work: 0.217 
  • R-Value Observed: 0.221 

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Structural Characterization and Membrane Localization of Exsb from the Type III Secretion System (T3Ss) of Pseudomonas Aeruginosa

Izore, T.Perdu, C.Job, V.Atree, I.Faudry, E.Dessen, A.

(2011) J Mol Biol 413: 236

  • DOI: https://doi.org/10.1016/j.jmb.2011.07.043
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Pseudomonas aeruginosa is an opportunistic human pathogen that employs a finely tuned type III secretion system (T3SS) to inject toxins directly into the cytoplasm of target cells. ExsB is a 15.6-kDa protein encoded in a T3SS transcription regulation operon that displays high sequence similarity to YscW, a lipoprotein from Yersinia spp. whose genetic neighborhood also involves a transcriptional regulator, and has been shown to play a role in the stabilization of the outer membrane ring of the T3SS. Here, we show that ExsB is expressed in P. aeruginosa upon induction of the T3SS, and subcellular fractionation studies reveal that it is associated with the outer membrane. The high-resolution crystal structure of ExsB shows that it displays a compact β-sandwich fold with interdependent β-sheets. ExsB possesses a large patch of basic residues that could play a role in membrane recognition, and its structure is distinct from that of MxiM, a lipoprotein involved in secretin stabilization in Shigella, as well as from those of Pil lipoproteins involved in pilus biogenesis. These results reveal that small lipoproteins involved in formation of the outer membrane secretin ring display clear structural differences that may be related to the different functions they play in these systems.

  • Organizational Affiliation

    Bacterial Pathogenesis Group, Institut de Biologie Structurale (IBS), Université Grenoble I, France.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C
125Pseudomonas aeruginosa PAO1Mutation(s): 0 
Find proteins for P26994 (Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1))
Explore P26994 
Go to UniProtKB:  P26994
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP26994
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.81 Å
  • R-Value Free: 0.262 
  • R-Value Work: 0.217 
  • R-Value Observed: 0.221 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 124.155α = 90
b = 48.358β = 96.92
c = 71.602γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-08-10
    Type: Initial release
  • Version 1.1: 2011-10-12
    Changes: Database references