Crystal structure of the major pseudopilin from the type 2 secretion system of Vibrio vulnificus

Experimental Data Snapshot

  • Resolution: 1.86 Å
  • R-Value Free: 0.204 
  • R-Value Work: 0.178 
  • R-Value Observed: 0.179 

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This is version 1.3 of the entry. See complete history


Calcium is essential for the major pseudopilin in the type 2 secretion system.

Korotkov, K.V.Gray, M.D.Kreger, A.Turley, S.Sandkvist, M.Hol, W.G.

(2009) J Biol Chem 284: 25466-25470

  • DOI: https://doi.org/10.1074/jbc.C109.037655
  • Primary Citation of Related Structures:  
    3FU1, 3G20, 3GN9

  • PubMed Abstract: 

    The pseudopilus is a key feature of the type 2 secretion system (T2SS) and is made up of multiple pseudopilins that are similar in fold to the type 4 pilins. However, pilins have disulfide bridges, whereas the major pseudopilins of T2SS do not. A key question is therefore how the pseudopilins, and in particular, the most abundant major pseudopilin, GspG, obtain sufficient stability to perform their function. Crystal structures of Vibrio cholerae, Vibrio vulnificus, and enterohemorrhagic Escherichia coli (EHEC) GspG were elucidated, and all show a calcium ion bound at the same site. Conservation of the calcium ligands fully supports the suggestion that calcium ion binding by the major pseudopilin is essential for the T2SS. Functional studies of GspG with mutated calcium ion-coordinating ligands were performed to investigate this hypothesis and show that in vivo protease secretion by the T2SS is severely impaired. Taking all evidence together, this allows the conclusion that, in complete contrast to the situation in the type 4 pili system homologs, in the T2SS, the major protein component of the central pseudopilus is dependent on calcium ions for activity.

  • Organizational Affiliation

    Department of Biochemistry, Biomolecular Structure Center, University of Washington, Seattle, Washington 98195, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Type II secretory pathway, pseudopilin EpsG
A, B, C
115Vibrio vulnificusMutation(s): 0 
Gene Names: EPSGVV1_0874
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.86 Å
  • R-Value Free: 0.204 
  • R-Value Work: 0.178 
  • R-Value Observed: 0.179 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 100.18α = 90
b = 104.51β = 106.16
c = 55.41γ = 90
Software Package:
Software NamePurpose
XSCALEdata scaling
PDB_EXTRACTdata extraction
Blu-Icedata collection
XDSdata reduction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-07-28
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.2: 2017-11-01
    Changes: Refinement description
  • Version 1.3: 2023-09-06
    Changes: Data collection, Database references, Derived calculations, Refinement description