Salmonella enterica SafA pilin, head-to-tail swapped dimer of Ntd1 mutant

Experimental Data Snapshot

  • Resolution: 1.78 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.184 
  • R-Value Observed: 0.184 

wwPDB Validation   3D Report Full Report

This is version 1.3 of the entry. See complete history


Donor-Strand Exchange in Chaperone-Assisted Pilus Assembly Proceeds Through a Concerted Beta-Strand Displacement Mechanism

Remaut, H.Rose, R.J.Hannan, T.J.Hultgren, S.J.Radford, S.E.Ashcroft, A.E.Waksman, G.

(2006) Mol Cell 22: 831

  • DOI: https://doi.org/10.1016/j.molcel.2006.05.033
  • Primary Citation of Related Structures:  
    2CNY, 2CNZ, 2CO1, 2CO2, 2CO3, 2CO4, 2CO6, 2CO7

  • PubMed Abstract: 

    Gram-negative pathogens commonly use the chaperone-usher pathway to assemble adhesive multisubunit fibers on their surface. In the periplasm, subunits are stabilized by a chaperone that donates a beta strand to complement the subunits' truncated immunoglobulin-like fold. Pilus assembly proceeds through a "donor-strand exchange" (DSE) mechanism whereby this complementary beta strand is replaced by the N-terminal extension (Nte) of an incoming pilus subunit. Using X-ray crystallography and real-time electrospray ionization mass spectrometry (ESI-MS), we demonstrate that DSE requires the formation of a transient ternary complex between the chaperone-subunit complex and the Nte of the next subunit to be assembled. The process is crucially dependent on an initiation site (the P5 pocket) needed to recruit the incoming Nte. The data also suggest a capping reaction displacing DSE toward product formation. These results support a zip-in-zip-out mechanism for DSE and a catalytic role for the usher, the molecular platform at which pili are assembled.

  • Organizational Affiliation

    Department of Molecular Microbiology, Washington University Medical School, 660 South Euclid Avenue, St. Louis, Missouri 63105.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
137Salmonella enterica subsp. enterica serovar Typhimurium str. LT2Mutation(s): 0 
Find proteins for Q8ZRK4 (Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720))
Explore Q8ZRK4 
Go to UniProtKB:  Q8ZRK4
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8ZRK4
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.78 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.184 
  • R-Value Observed: 0.184 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 50.373α = 90
b = 41.216β = 104.13
c = 59.92γ = 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: 2006-06-27
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2018-04-04
    Changes: Data collection