Structure of Salmonella Typhi TtsA

Experimental Data Snapshot

  • Resolution: 2.10 Å
  • R-Value Free: 0.222 
  • R-Value Work: 0.191 
  • R-Value Observed: 0.193 

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Mechanisms of substrate recognition by a typhoid toxin secretion-associated muramidase.

Geiger, T.Lara-Tejero, M.Xiong, Y.Galan, J.E.

(2020) Elife 9

  • DOI: https://doi.org/10.7554/eLife.53473
  • Primary Citation of Related Structures:  
    6V3Z, 6V40

  • PubMed Abstract: 

    Typhoid toxin is a virulence factor for the bacterial pathogen Salmonella Typhi, which causes typhoid fever in humans. After its synthesis by intracellular bacteria, typhoid toxin is secreted into the lumen of the Salmonella -containing vacuole by a secretion mechanism strictly dependent on TtsA, a specific muramidase that facilitates toxin transport through the peptidoglycan layer. Here we show that substrate recognition by TtsA depends on a discrete domain within its carboxy terminus, which targets the enzyme to the bacterial poles to recognize YcbB-edited peptidoglycan. Comparison of the atomic structures of TtsA bound to its substrate and that of a close homolog with different specificity identified specific determinants involved in substrate recognition. Combined with structure-guided mutagenesis and in vitro and in vivo crosslinking experiments, this study provides an unprecedented view of the mechanisms by which a muramidase recognizes its peptidoglycan substrate to facilitate protein secretion.

  • Organizational Affiliation

    Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, United States.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
PG_binding_3 domain-containing protein
A, B, C, D
197Salmonella enterica subsp. enterica serovar TyphiMutation(s): 0 
Gene Names: STY1889
Find proteins for Q8Z6A5 (Salmonella typhi)
Explore Q8Z6A5 
Go to UniProtKB:  Q8Z6A5
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8Z6A5
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.10 Å
  • R-Value Free: 0.222 
  • R-Value Work: 0.191 
  • R-Value Observed: 0.193 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 136.985α = 90
b = 138.607β = 90
c = 135.199γ = 90
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)United States2R01AI114618-06

Revision History  (Full details and data files)

  • Version 1.0: 2020-01-29
    Type: Initial release
  • Version 2.0: 2023-11-15
    Changes: Atomic model, Data collection, Database references, Refinement description