Biological Assembly 1  

 3D View: Structure | 1D-3D View | Electron Density | Validation Report

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 2-mer - A1B1 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 31.71 kDa 
• Atom Count: 1238 
• Modelled Residue Count: 156 
• Deposited Residue Count: 287 
• Unique protein chains: 2

1XOU

Crystal structure of the CesA-EspA complex

• PDB DOI: 10.2210/pdb1XOU/pdb

• Classification: Structural protein/chaperone
• Organism(s): Escherichia coli
• Expression System: Escherichia coli BL21
• Mutation(s): Yes 


• Deposited: 2004-10-06 Released: 2004-12-28 
• Deposition Author(s): Yip, C.K., Finlay, B.B., Strynadka, N.C.J.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.80 Å
• R-Value Free: 0.265 
• R-Value Work: 0.236 
• R-Value Observed: 0.236 

Literature

Structural characterization of a type III secretion system filament protein in complex with its chaperone.

Yip, C.K., Finlay, B.B., Strynadka, N.C.J.

(2005) Nat Struct Mol Biol 12: 75-81

• PubMed: 15619638 
• DOI: 10.1038/nsmb879
• Primary Citation of Related Structures:  
  1XOU


• PubMed Abstract: 
  

The type III secretion system (TTSS) mediates the specific translocation of bacterial proteins into the cytoplasm of eukaryotic cells, a process essential for the virulence of many Gram-negative pathogens. The enteropathogenic Escherichia coli TTSS protein EspA forms a hollow extracellular filament believed to be a molecular conduit for type III protein translocation. Structural analysis of EspA has been hampered by its polymeric nature. We show that EspA alone is sufficient to form filamentous structures in the absence of other pathogenicity island-encoded proteins. CesA is the recently proposed chaperone of EspA, and we demonstrate that CesA traps EspA in a monomeric state and inhibits its polymerization. Crystallographic analysis of the heterodimeric CesA-EspA complex at a resolution of 2.8 A reveals that EspA contains two long a-helices, which are involved in extensive coiled-coil interactions with CesA.

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Organizational Affiliation: 

Department of Biochemistry and Molecular Biology, University of British Columbia, 2146 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
EspA	A	192	Escherichia coli	Mutation(s): 9  Gene Names: espA, D3G36_09190, NCTC10089_00097
UniProt
Find proteins for Q47184 (Escherichia coli) Explore Q47184  Go to UniProtKB:  Q47184

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
Z5138 gene product	B	95	Escherichia coli	Mutation(s): 2  Gene Names: orf3, cesAB, BFL24_25155, BON63_23780, C9E67_00525, DAH23_17650, L537_062, LDEC_054, LIHIT_058, UN91_09460
UniProt
Find proteins for O52124 (Escherichia coli) Explore O52124  Go to UniProtKB:  O52124

Small Molecules

Modified Residues  1 Unique
ID	Chains	Type	Formula	2D Diagram	Parent
MSE	A	L-PEPTIDE LINKING	C5 H11 N O2 Se		MET

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.80 Å
• R-Value Free: 0.265 
• R-Value Work: 0.236 
• R-Value Observed: 0.236 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 35.422	α = 90
b = 72.383	β = 90
c = 95.679	γ = 90

Software Package:

Software Name	Purpose
CNS	refinement
MOSFLM	data reduction
CCP4	data scaling
SOLVE	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2004-10-06 
• Released Date: 2004-12-28 
Deposition Author(s): Yip, C.K., Finlay, B.B., Strynadka, N.C.J.

Revision History  

• Version 1.0: 2004-12-28
  Type: Initial release
  
• Version 1.1: 2008-04-30
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance
• Version 1.3: 2021-10-20
  Changes: Database references, Derived calculations