Crystal Structure of FosB from Staphylococcus aureus with Zn and Sulfate at 1.15 Angstrom Resolution

Experimental Data Snapshot

  • Resolution: 1.15 Å
  • R-Value Free: 0.163 
  • R-Value Work: 0.134 
  • R-Value Observed: 0.136 

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Structure and Function of the Genomically Encoded Fosfomycin Resistance Enzyme, FosB, from Staphylococcus aureus.

Thompson, M.K.Keithly, M.E.Goodman, M.C.Hammer, N.D.Cook, P.D.Jagessar, K.L.Harp, J.Skaar, E.P.Armstrong, R.N.

(2014) Biochemistry 53: 755-765

  • DOI: https://doi.org/10.1021/bi4015852
  • Primary Citation of Related Structures:  
    4NAY, 4NAZ, 4NB0, 4NB1, 4NB2

  • PubMed Abstract: 

    The Gram-positive pathogen Staphylococcus aureus is a leading cause of global morbidity and mortality. Like many multi-drug-resistant organisms, S. aureus contains antibiotic-modifying enzymes that facilitate resistance to a multitude of antimicrobial compounds. FosB is a Mn(2+)-dependent fosfomycin-inactivating enzyme found in S. aureus that catalyzes nucleophilic addition of either l-cysteine (l-Cys) or bacillithiol (BSH) to the antibiotic, resulting in a modified compound with no bactericidal properties. The three-dimensional X-ray crystal structure of FosB from S. aureus (FosB(Sa)) has been determined to a resolution of 1.15 Å. Cocrystallization of FosB(Sa) with either l-Cys or BSH results in a disulfide bond between the exogenous thiol and the active site Cys9 of the enzyme. An analysis of the structures suggests that a highly conserved loop region of the FosB enzymes must change conformation to bind fosfomycin. While two crystals of FosB(Sa) contain Zn(2+) in the active site, kinetic analyses of FosB(Sa) indicated that the enzyme is inhibited by Zn(2+) for l-Cys transferase activity and only marginally active for BSH transferase activity. Fosfomycin-treated disk diffusion assays involving S. aureus Newman and the USA300 JE2 methicillin-resistant S. aureus demonstrate a marked increase in the sensitivity of the organism to the antibiotic in either the BSH or FosB null strains, indicating that both are required for survival of the organism in the presence of the antibiotic. This work identifies FosB as a primary fosfomycin-modifying pathway of S. aureus and establishes the enzyme as a potential therapeutic target for increased efficacy of fosfomycin against the pathogen.

  • Organizational Affiliation

    Department of Biochemistry, Vanderbilt University School of Medicine , Nashville, Tennessee 37232, United States.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Metallothiol transferase FosB145Staphylococcus aureus subsp. aureus N315Mutation(s): 0 
Gene Names: fosBSA2124
EC: 2.5.1
Find proteins for P60864 (Staphylococcus aureus (strain N315))
Explore P60864 
Go to UniProtKB:  P60864
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP60864
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.15 Å
  • R-Value Free: 0.163 
  • R-Value Work: 0.134 
  • R-Value Observed: 0.136 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 62.616α = 90
b = 62.808β = 122.08
c = 45.053γ = 90
Software Package:
Software NamePurpose
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
HKL-2000data collection
HKL-2000data reduction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-02-26
    Type: Initial release
  • Version 1.1: 2014-04-16
    Changes: Structure summary
  • Version 1.2: 2024-02-28
    Changes: Data collection, Database references, Derived calculations