Experimental Data Snapshot

  • Resolution: 2.00 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.205 
  • R-Value Observed: 0.205 

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This is version 1.3 of the entry. See complete history


Structure of TcpG, the DsbA protein folding catalyst from Vibrio cholerae.

Hu, S.H.Peek, J.A.Rattigan, E.Taylor, R.K.Martin, J.L.

(1997) J Mol Biol 268: 137-146

  • DOI: https://doi.org/10.1006/jmbi.1997.0940
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The efficient and correct folding of bacterial disulfide bonded proteins in vivo is dependent upon a class of periplasmic oxidoreductase proteins called DsbA, after the Escherichia coli enzyme. In the pathogenic bacterium Vibrio cholerae, the DsbA homolog (TcpG) is responsible for the folding, maturation and secretion of virulence factors. Mutants in which the tcpg gene has been inactivated are avirulent; they no longer produce functional colonisation pili and they no longer secrete cholera toxin. TcpG is thus a suitable target for inhibitors that could counteract the virulence of this organism, thereby preventing the symptoms of cholera. The crystal structure of oxidized TcpG (refined at a resolution of 2.1 A) serves as a starting point for the rational design of such inhibitors. As expected, TcpG has the same fold as E. coli DsbA, with which it shares approximately 40% sequence identity. In addition, the characteristic surface features of DsbA are present in TcpG, supporting the notion that these features play a functional role. While the overall architecture of TcpG and DsbA is similar and the surface features are retained in TcpG, there are significant differences. For example, the kinked active site helix results from a three-residue loop in DsbA, but is caused by a proline in TcpG (making TcpG more similar to thioredoxin in this respect). Furthermore, the proposed peptide binding groove of TcpG is substantially shortened compared with that of DsbA due to a six-residue deletion. Also, the hydrophobic pocket of TcpG is more shallow and the acidic patch is much less extensive than that of E. coli DsbA. The identification of the structural and surface features that are retained or are divergent in TcpG provides a useful assessment of their functional importance in these protein folding catalysts and is an important prerequisite for the design of TcpG inhibitors.

  • Organizational Affiliation

    Centre for Drug Design and Development, University of Queensland, Brisbane, Australia.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
DSBA OXIDOREDUCTASE181Vibrio choleraeMutation(s): 0 
Find proteins for P32557 (Vibrio cholerae serotype O1 (strain ATCC 39315 / El Tor Inaba N16961))
Explore P32557 
Go to UniProtKB:  P32557
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP32557
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.00 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.205 
  • R-Value Observed: 0.205 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 64α = 90
b = 91.5β = 90
c = 64.8γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
X-PLORmodel building

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1997-10-08
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-08-02
    Changes: Database references, Refinement description