MxiH needle protein of Shigella Flexneri (monomeric form, residues 1- 78)

Experimental Data Snapshot

  • Resolution: 2.10 Å
  • R-Value Work: 0.194 
  • R-Value Observed: 0.194 

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Molecular Model of a Type III Secretion System Needle: Implications for Host-Cell Sensing

Deane, J.E.Roversi, P.Cordes, F.S.Johnson, S.Kenjale, R.Daniell, S.Booy, F.Picking, W.L.Picking, W.D.Blocker, A.J.Lea, S.M.

(2006) Proc Natl Acad Sci U S A 103: 12529

  • DOI: https://doi.org/10.1073/pnas.0602689103
  • Primary Citation of Related Structures:  
    2CA5, 2V6L

  • PubMed Abstract: 

    Type III secretion systems are essential virulence determinants for many Gram-negative bacterial pathogens. The type III secretion system consists of cytoplasmic, transmembrane, and extracellular domains. The extracellular domain is a hollow needle protruding above the bacterial surface and is held within a basal body that traverses both bacterial membranes. Effector proteins are translocated, via this external needle, directly into host cells, where they subvert normal cell functions to aid infection. Physical contact with host cells initiates secretion and leads to formation of a pore, thought to be contiguous with the needle channel, in the host-cell membrane. Here, we report the crystal structure of the Shigella flexneri needle subunit MxiH and a complete model for the needle assembly built into our three-dimensional EM reconstruction. The model, combined with mutagenesis data, reveals that signaling of host-cell contact is relayed through the needle via intersubunit contacts and suggests a mode of binding for a tip complex.

  • Organizational Affiliation

    Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
85Shigella flexneriMutation(s): 0 
Find proteins for P0A223 (Shigella flexneri)
Explore P0A223 
Go to UniProtKB:  P0A223
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0A223
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.10 Å
  • R-Value Work: 0.194 
  • R-Value Observed: 0.194 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 183.203α = 90
b = 28.123β = 96.47
c = 27.723γ = 90
Software Package:
Software NamePurpose
SIGMAAmodel building
SCALAdata scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-08-07
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2024-05-08
    Changes: Data collection, Database references, Derived calculations, Other