AtxA protein, a virulence regulator from Bacillus anthracis.

Experimental Data Snapshot

  • Resolution: 2.65 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.199 

wwPDB Validation   3D Report Full Report

This is version 1.3 of the entry. See complete history


Crystal structure of Bacillus anthracis virulence regulator AtxA and effects of phosphorylated histidines on multimerization and activity.

Hammerstrom, T.G.Horton, L.B.Swick, M.C.Joachimiak, A.Osipiuk, J.Koehler, T.M.

(2015) Mol Microbiol 95: 426-441

  • DOI: https://doi.org/10.1111/mmi.12867
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The Bacillus anthracis virulence regulator AtxA controls transcription of the anthrax toxin genes and capsule biosynthetic operon. AtxA activity is elevated during growth in media containing glucose and CO(2)/bicarbonate, and there is a positive correlation between the CO(2)/bicarbonate signal, AtxA activity and homomultimerization. AtxA activity is also affected by phosphorylation at specific histidines. We show that AtxA crystallizes as a dimer. Distinct folds associated with predicted DNA-binding domains (HTH1 and HTH2) and phosphoenolpyruvate: carbohydrate phosphotransferase system-regulated domains (PRD1 and PRD2) are apparent. We tested AtxA variants containing single and double phosphomimetic (His→Asp) and phosphoablative (His→Ala) amino acid changes for activity in B. anthracis cultures and for protein-protein interactions in cell lysates. Reduced activity of AtxA H199A, lack of multimerization and activity of AtxAH379D variants, and predicted structural changes associated with phosphorylation support a model for control of AtxA function. We propose that (i) in the AtxA dimer, phosphorylation of H199 in PRD1 affects HTH2 positioning, influencing DNA-binding; and (ii) phosphorylation of H379 in PRD2 disrupts dimer formation. The AtxA structure is the first reported high-resolution full-length structure of a PRD-containing regulator, and can serve as a model for proteins of this family, especially those that link virulence to bacterial metabolism.

  • Organizational Affiliation

    Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center at Houston, Houston, TX, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Anthrax toxin expression trans-acting positive regulator
A, B
478Bacillus anthracis str. 'Ames AncestorMutation(s): 0 
Gene Names: atxABXA0146GBAA_pXO1_0146pXO1-119
Find proteins for Q44636 (Bacillus anthracis)
Explore Q44636 
Go to UniProtKB:  Q44636
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ44636
Sequence Annotations
  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
Query on MSE
A, B
Experimental Data & Validation

Experimental Data

Unit Cell:
Length ( Å )Angle ( ˚ )
a = 130.46α = 90
b = 135.167β = 90
c = 180.908γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
SBC-Collectdata collection
HKL-3000data reduction
HKL-3000data scaling

Structure Validation

View Full Validation Report

Entry History 

Revision History  (Full details and data files)

  • Version 1.0: 2014-10-22
    Type: Initial release
  • Version 1.1: 2014-12-03
    Changes: Database references
  • Version 1.2: 2015-02-11
    Changes: Database references
  • Version 1.3: 2017-11-22
    Changes: Refinement description