4EE2

Crystal Structure of Anthrax Protective Antigen K446M Mutant to 1.91-A Resolution


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.91 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.229 
  • R-Value Observed: 0.231 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Anthrax toxin protective antigen integrates poly-gamma-D-glutamate and pH signals to sense the optimal environment for channel formation.

Kintzer, A.F.Tang, I.I.Schawel, A.K.Brown, M.J.Krantz, B.A.

(2012) Proc Natl Acad Sci U S A 109: 18378-18383

  • DOI: https://doi.org/10.1073/pnas.1208280109
  • Primary Citation of Related Structures:  
    4EE2

  • PubMed Abstract: 

    Many toxins assemble into oligomers on the surface of cells. Local chemical cues signal and trigger critical rearrangements of the oligomer, inducing the formation of a membrane-fused or channel state. Bacillus anthracis secretes two virulence factors: a tripartite toxin and a poly-γ-d-glutamic acid capsule (γ-DPGA). The toxin's channel-forming component, protective antigen (PA), oligomerizes to create a prechannel that forms toxic complexes upon binding the two other enzyme components, lethal factor (LF) and edema factor (EF). Following endocytosis into host cells, acidic pH signals the prechannel to form the channel state, which translocates LF and EF into the host cytosol. We report γ-DPGA binds to PA, LF, and EF, exhibiting nanomolar avidity for the PA prechannel oligomer. We show PA channel formation requires the pH-dependent disruption of the intra-PA domain-2-domain-4 (D2-D4) interface. γ-DPGA stabilizes the D2-D4 interface, preventing channel formation both in model membranes and cultured mammalian cells. A 1.9-Å resolution X-ray crystal structure of a D2-D4-interface mutant and corresponding functional studies reveal how stability at the intra-PA interface governs channel formation. We also pinpoint the kinetic pH trigger for channel formation to a residue within PA's membrane-insertion loop at the inter-PA D2-D4 interface. Thus, γ-DPGA may function as a chemical cue, signaling that the local environment is appropriate for toxin assembly but inappropriate for channel formation.


  • Organizational Affiliation

    Department of Chemistry, University of California, Berkeley, CA 94720, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Protective antigen736Bacillus anthracisMutation(s): 1 
Gene Names: pagApagpXO1-110BXA0164GBAA_pXO1_0164
UniProt
Find proteins for P13423 (Bacillus anthracis)
Explore P13423 
Go to UniProtKB:  P13423
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP13423
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.91 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.229 
  • R-Value Observed: 0.231 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 71.216α = 90
b = 93.512β = 90
c = 116.918γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PHASERphasing
PHENIXrefinement
PDB_EXTRACTdata extraction
ADSCdata collection
HKL-2000data reduction

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-10-24
    Type: Initial release
  • Version 1.1: 2013-09-04
    Changes: Database references
  • Version 1.2: 2017-11-15
    Changes: Refinement description
  • Version 1.3: 2023-09-13
    Changes: Data collection, Database references, Derived calculations, Refinement description