3TUL

Crystal structure of N-terminal region of Type III Secretion Major Translocator SipB (residues 82-226)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.793 Å
  • R-Value Free: 0.316 
  • R-Value Work: 0.298 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

The Structures of Coiled-Coil Domains from Type III Secretion System Translocators Reveal Homology to Pore-Forming Toxins.

Barta, M.L.Dickenson, N.E.Patil, M.Keightley, A.Wyckoff, G.J.Picking, W.D.Picking, W.L.Geisbrecht, B.V.

(2012) J.Mol.Biol. 417: 395-405

  • DOI: 10.1016/j.jmb.2012.01.026
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Many pathogenic Gram-negative bacteria utilize type III secretion systems (T3SSs) to alter the normal functions of target cells. Shigella flexneri uses its T3SS to invade human intestinal cells to cause bacillary dysentery (shigellosis) that is respo ...

    Many pathogenic Gram-negative bacteria utilize type III secretion systems (T3SSs) to alter the normal functions of target cells. Shigella flexneri uses its T3SS to invade human intestinal cells to cause bacillary dysentery (shigellosis) that is responsible for over one million deaths per year. The Shigella type III secretion apparatus is composed of a basal body spanning both bacterial membranes and an exposed oligomeric needle. Host altering effectors are secreted through this energized unidirectional conduit to promote bacterial invasion. The active needle tip complex of S. flexneri is composed of a tip protein, IpaD, and two pore-forming translocators, IpaB and IpaC. While the atomic structure of IpaD has been elucidated and studied, structural data on the hydrophobic translocators from the T3SS family remain elusive. We present here the crystal structures of a protease-stable fragment identified within the N-terminal regions of IpaB from S. flexneri and SipB from Salmonella enterica serovar Typhimurium determined at 2.1 Å and 2.8 Å limiting resolution, respectively. These newly identified domains are composed of extended-length (114 Å in IpaB and 71 Å in SipB) coiled-coil motifs that display a high degree of structural homology to one another despite the fact that they share only 21% sequence identity. Further structural comparisons also reveal substantial similarity to the coiled-coil regions of pore-forming proteins from other Gram-negative pathogens, notably, colicin Ia. This suggests that these mechanistically separate and functionally distinct membrane-targeting proteins may have diverged from a common ancestor during the course of pathogen-specific evolutionary events.


    Organizational Affiliation

    School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Cell invasion protein sipB
A, B, C, D
158Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720)Mutation(s): 0 
Gene Names: sipB (sspB)
Find proteins for Q56019 (Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720))
Go to UniProtKB:  Q56019
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MSE
Query on MSE
A, B, C, D
L-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.793 Å
  • R-Value Free: 0.316 
  • R-Value Work: 0.298 
  • Space Group: P 21 2 21
Unit Cell:
Length (Å)Angle (°)
a = 159.154α = 90.00
b = 51.144β = 90.00
c = 84.646γ = 90.00
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
HKL-2000data scaling
PHENIXrefinement
HKL-2000data reduction
SOLVEphasing
HKL-2000data collection

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-02-15
    Type: Initial release
  • Version 1.1: 2012-02-22
    Type: Database references
  • Version 1.2: 2012-03-28
    Type: Database references