Crystal structure of the minor pseudopilin EPSH from the type II secretion system of Vibrio cholerae

Experimental Data Snapshot

  • Resolution: 1.59 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.201 
  • R-Value Observed: 0.204 

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The 1.59 angstrom resolution structure of the minor pseudopilin EpsH of Vibrio cholerae reveals a long flexible loop.

Raghunathan, K.Vago, F.S.Grindem, D.Ball, T.Wedemeyer, W.J.Bagdasarian, M.Arvidson, D.N.

(2013) Biochim Biophys Acta 1844: 406-415

  • DOI: https://doi.org/10.1016/j.bbapap.2013.11.013
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The type II secretion complex exports folded proteins from the periplasm to the extracellular milieu. It is used by the pathogenic bacterium Vibrio cholerae to export several proteins, including its major virulence factor, cholera toxin. The pseudopilus is an essential component of the type II secretion system and likely acts as a piston to push the folded proteins across the outer membrane through the secretin pore. The pseudopilus is composed of the major pseudopilin, EpsG, and four minor pseudopilins, EpsH, EpsI, EpsJ and EpsK. We determined the x-ray crystal structure of the head domain of EpsH at 1.59Å resolution using molecular replacement with the previously reported EpsH structure, 2qv8, as the template. Three additional N-terminal amino acids present in our construct prevent an artifactual conformation of residues 160-166, present in one of the two monomers of the 2qv8 structure. Additional crystal contacts stabilize a long flexible loop comprised of residues 104-135 that is more disordered in the 2qv8 structure but is partially observed in our structure in very different positions for the two EpsH monomers in the asymmetric unit. In one of the conformations the loop is highly extended. Modeling suggests the highly charged loop is capable of contacting EpsG and possibly secreted protein substrates, suggesting a role in specificity of pseudopilus assembly or secretion function.

  • Organizational Affiliation

    Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA; Center for Microbial Pathogenesis, Michigan State University, East Lansing, MI 48824, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
General secretion pathway protein H
A, B
170Vibrio choleraeMutation(s): 0 
Gene Names: epsHVC_2729
Find proteins for P45774 (Vibrio cholerae serotype O1 (strain ATCC 39315 / El Tor Inaba N16961))
Explore P45774 
Go to UniProtKB:  P45774
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP45774
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.59 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.201 
  • R-Value Observed: 0.204 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 53.391α = 90
b = 71.11β = 90
c = 84.646γ = 90
Software Package:
Software NamePurpose
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: 2013-03-13
    Type: Initial release
  • Version 1.1: 2014-01-08
    Changes: Database references
  • Version 1.2: 2024-02-28
    Changes: Data collection, Database references, Derived calculations