Pseudomonas Aeruginosa Exotoxin A, wild type

Experimental Data Snapshot

  • Resolution: 1.62 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.209 
  • R-Value Observed: 0.209 

Starting Model: experimental
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This is version 1.4 of the entry. See complete history


Refined Crystallographic Structure of Pseudomonas aeruginosa Exotoxin A and its Implications for the Molecular Mechanism of Toxicity

Wedekind, J.E.Trame, C.B.Dorywalska, M.Koehl, P.Raschke, T.M.McKee, M.FitzGerald, D.Collier, R.J.McKay, D.B.

(2001) J Mol Biol 314: 823-837

  • DOI: https://doi.org/10.1006/jmbi.2001.5195
  • Primary Citation of Related Structures:  
    1IKP, 1IKQ

  • PubMed Abstract: 

    Exotoxin A of Pseudomonas aeruginosa asserts its cellular toxicity through ADP-ribosylation of translation elongation factor 2, predicated on binding to specific cell surface receptors and intracellular trafficking via a complex pathway that ultimately results in translocation of an enzymatic activity into the cytoplasm. In early work, the crystallographic structure of exotoxin A was determined to 3.0 A resolution, revealing a tertiary fold having three distinct structural domains; subsequent work has shown that the domains are individually responsible for the receptor binding (domain I), transmembrane targeting (domain II), and ADP-ribosyl transferase (domain III) activities, respectively. Here, we report the structures of wild-type and W281A mutant toxin proteins at pH 8.0, refined with data to 1.62 A and 1.45 A resolution, respectively. The refined models clarify several ionic interactions within structural domains I and II that may modulate an obligatory conformational change that is induced by low pH. Proteolytic cleavage by furin is also obligatory for toxicity; the W281A mutant protein is substantially more susceptible to cleavage than the wild-type toxin. The tertiary structures of the furin cleavage sites of the wild-type and W281 mutant toxins are similar; however, the mutant toxin has significantly higher B-factors around the cleavage site, suggesting that the greater susceptibility to furin cleavage is due to increased local disorder/flexibility at the site, rather than to differences in static tertiary structure. Comparison of the refined structures of full-length toxin, which lacks ADP-ribosyl transferase activity, to that of the enzymatic domain alone reveals a salt bridge between Arg467 of the catalytic domain and Glu348 of domain II that restrains the substrate binding cleft in a conformation that precludes NAD+ binding. The refined structures of exotoxin A provide precise models for the design and interpretation of further studies of the mechanism of intoxication.

  • Organizational Affiliation

    Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
EXOTOXIN A613Pseudomonas aeruginosaMutation(s): 0 
Gene Names: PE
EC: 2.4.2
Find proteins for P11439 (Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1))
Explore P11439 
Go to UniProtKB:  P11439
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP11439
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.62 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.209 
  • R-Value Observed: 0.209 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 59.52α = 90
b = 98.12β = 97.3
c = 58.26γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2001-12-12
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2018-01-31
    Changes: Database references
  • Version 1.4: 2024-04-03
    Changes: Data collection, Database references, Derived calculations, Refinement description