C-terminally extended and N-terminally truncated variant of FimA E. coli at 1.5 Angstrom resolution

Experimental Data Snapshot

  • Resolution: 1.50 Å
  • R-Value Free: 0.206 
  • R-Value Work: 0.169 
  • R-Value Observed: 0.170 

wwPDB Validation   3D Report Full Report

This is version 1.3 of the entry. See complete history


Donor strand sequence, rather than donor strand orientation, determines the stability and non-equilibrium folding of the type 1 pilus subunit FimA.

Zyla, D.Echeverria, B.Glockshuber, R.

(2020) J Biol Chem 295: 12437-12448

  • DOI: https://doi.org/10.1074/jbc.RA120.014324
  • Primary Citation of Related Structures:  
    6R74, 6R7E, 6S09

  • PubMed Abstract: 

    FimA is the main structural subunit of adhesive type 1 pili from uropathogenic Escherichia coli strains. Up to 3000 copies of FimA assemble to the helical pilus rod through a mechanism termed donor strand complementation, in which the incomplete immunoglobulin-like fold of each FimA subunit is complemented by the N-terminal extension (Nte) of the next subunit. The Nte of FimA, which exhibits a pseudo-palindromic sequence, is inserted in an antiparallel orientation relative to the last β-strand of the preceding subunit in the pilus. The resulting subunit-subunit interactions are extraordinarily stable against dissociation and unfolding. Alternatively, FimA can fold to a self-complemented monomer with anti-apoptotic activity, in which the Nte inserts intramolecularly into the FimA core in the opposite, parallel orientation. The FimA monomers, however, show dramatically lower thermodynamic stability compared with FimA subunits in the assembled pilus. Using self-complemented FimA variants with reversed, pseudo-palindromic extensions, we demonstrate that the high stability of FimA polymers is primarily caused by the specific interactions between the side chains of the Nte residues and the FimA core and not by the antiparallel orientation of the donor strand alone. In addition, we demonstrate that nonequilibrium two-state folding, a hallmark of FimA with the Nte inserted in the pilus rod-like, antiparallel orientation, only depends on the identity of the inserted Nte side chains and not on Nte orientation.

  • Organizational Affiliation

    Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
FimA166Escherichia coliMutation(s): 0 
Gene Names: fimA
Find proteins for P04128 (Escherichia coli (strain K12))
Explore P04128 
Go to UniProtKB:  P04128
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP04128
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.50 Å
  • R-Value Free: 0.206 
  • R-Value Work: 0.169 
  • R-Value Observed: 0.170 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 92.31α = 90
b = 105.23β = 90
c = 106.99γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
XSCALEdata scaling
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Swiss National Science FoundationSwitzerland310030B_176403/1
Swiss National Science FoundationSwitzerland31003A_156304

Revision History  (Full details and data files)

  • Version 1.0: 2020-07-15
    Type: Initial release
  • Version 1.1: 2020-08-12
    Changes: Database references
  • Version 1.2: 2020-09-09
    Changes: Database references
  • Version 1.3: 2024-01-24
    Changes: Data collection, Database references, Refinement description