Structure of fusion complex of homo trimeric major pilin subunits CfaB of CFA/I fimbirae from ETEC E. coli

Experimental Data Snapshot

  • Resolution: 2.10 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.233 
  • R-Value Observed: 0.236 

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This is version 1.2 of the entry. See complete history


Structure of CFA/I fimbriae from enterotoxigenic Escherichia coli.

Li, Y.F.Poole, S.Nishio, K.Jang, K.Rasulova, F.McVeigh, A.Savarino, S.J.Xia, D.Bullitt, E.

(2009) Proc Natl Acad Sci U S A 106: 10793-10798

  • DOI: https://doi.org/10.1073/pnas.0812843106
  • Primary Citation of Related Structures:  
    3F83, 3F84, 3F85

  • PubMed Abstract: 

    Adhesion pili (fimbriae) play a critical role in initiating the events that lead to intestinal colonization and diarrheal disease by enterotoxigenic Escherichia coli (ETEC), an E. coli pathotype that inflicts an enormous global disease burden. We elucidate atomic structures of an ETEC major pilin subunit, CfaB, from colonization factor antigen I (CFA/I) fimbriae. These data are used to construct models for 2 morphological forms of CFA/I fimbriae that are both observed in vivo: the helical filament into which it is typically assembled, and an extended, unwound conformation. Modeling and corroborative mutational data indicate that proline isomerization is involved in the conversion between these helical and extended forms. Our findings affirm the strong structural similarities seen between class 5 fimbriae (from bacteria primarily causing gastrointestinal disease) and class 1 pili (from bacteria that cause urinary, respiratory, and other infections) in the absence of significant primary sequence similarity. They also suggest that morphological and biochemical differences between fimbrial types, regardless of class, provide structural specialization that facilitates survival of each bacterial pathotype in its preferred host microenvironment. Last, we present structural evidence for bacterial use of antigenic variation to evade host immune responses, in that residues occupying the predicted surface-exposed face of CfaB and related class 5 pilins show much higher genetic sequence variability than the remainder of the pilin protein.

  • Organizational Affiliation

    Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4256, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
homo trimeric fusion of CFA/I fimbrial subunits B463Escherichia coliMutation(s): 0 
Find proteins for E3PPC4 (Escherichia coli O78:H11 (strain H10407 / ETEC))
Explore E3PPC4 
Go to UniProtKB:  E3PPC4
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupE3PPC4
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.10 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.233 
  • R-Value Observed: 0.236 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 127.406α = 90
b = 44.982β = 125.35
c = 97.88γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-08-11
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.2: 2017-08-16
    Changes: Refinement description, Source and taxonomy