Crystal Structure of the C-terminal half of the Vibrio cholerae minor pilin TcpB

Experimental Data Snapshot

  • Resolution: 1.53 Å
  • R-Value Free: 0.198 
  • R-Value Work: 0.178 
  • R-Value Observed: 0.179 

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TheVibrio choleraeminor pilin TcpB mediates uptake of the cholera toxin phage CTX phi.

Gutierrez-Rodarte, M.Kolappan, S.Burrell, B.A.Craig, L.

(2019) J Biol Chem 294: 15698-15710

  • DOI: https://doi.org/10.1074/jbc.RA119.009980
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Virulent strains of the bacterial pathogen Vibrio cholerae cause the diarrheal disease cholera by releasing cholera toxin into the small intestine. V. cholerae acquired its cholera toxin genes by lysogenic infection with the filamentous bacteriophage CTXφ. CTXφ uses its minor coat protein pIII, located in multiple copies at the phage tip, to bind to the V. cholerae toxin-coregulated pilus (TCP). However, the molecular details of this interaction and the mechanism of phage internalization are not well-understood. The TCP filament is a polymer of major pilins, TcpA, and one or more minor pilin, TcpB. TCP are retractile, with both retraction and assembly initiated by TcpB. Consistent with these roles in pilus dynamics, we hypothesized that TcpB controls both binding and internalization of CTXφ. To test this hypothesis, we determined the crystal structure of the C-terminal half of TcpB and characterized its interactions with CTXφ pIII. We show that TcpB is a homotrimer in its crystallographic form as well as in solution and is present in multiple copies at the pilus tip, which likely facilitates polyvalent binding to pIII proteins at the phage tip. We further show that recombinant forms of TcpB and pIII interact in vitro , and both TcpB and anti-TcpB antibodies block CTXφ infection of V. cholerae Finally, we show that CTXφ uptake requires TcpB-mediated retraction. Our data support a model whereby CTXφ and TCP bind in a tip-to-tip orientation, allowing the phage to be drawn into the V. cholerae periplasm as an extension of the pilus filament.

  • Organizational Affiliation

    Molecular Biology and Biochemistry Department, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada licraig@sfu.ca.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Toxin co-regulated pilus biosynthesis protein B185Vibrio cholerae O395Mutation(s): 0 
Gene Names: tcpBVC0395_A0354
Find proteins for A0A0H3AKH0 (Vibrio cholerae serotype O1 (strain ATCC 39541 / Classical Ogawa 395 / O395))
Explore A0A0H3AKH0 
Go to UniProtKB:  A0A0H3AKH0
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A0H3AKH0
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.53 Å
  • R-Value Free: 0.198 
  • R-Value Work: 0.178 
  • R-Value Observed: 0.179 
  • Space Group: H 3 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 63.29α = 90
b = 63.29β = 90
c = 236.291γ = 120
Software Package:
Software NamePurpose
iMOSFLMdata reduction
Aimlessdata scaling

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Canadian Institutes of Health Research (CIHR)CanadaMOP125959

Revision History  (Full details and data files)

  • Version 1.0: 2019-08-28
    Type: Initial release
  • Version 1.1: 2019-11-13
    Changes: Database references
  • Version 1.2: 2020-01-08
    Changes: Author supporting evidence
  • Version 1.3: 2023-10-11
    Changes: Data collection, Database references, Refinement description