1K3E | pdb_00001k3e

Type III secretion chaperone CesT

• PDB DOI: https://doi.org/10.2210/pdb1K3E/pdb

• Classification: CHAPERONE
• Organism(s): Escherichia coli O157:H7
• Expression System: Escherichia coli BL21(DE3)
• Mutation(s): No 


• Deposited: 2001-10-02 Released: 2001-11-28 
• Deposition Author(s): Luo, Y., Bertero, M., Frey, E.A., Pfuetzner, R.A., Wenk, M.R., Creagh, L., Marcus, S.L., Lim, D., 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: 
  0.285 (Depositor), 0.285 (DCC) 
• R-Value Work: 
  0.225 (Depositor), 0.228 (DCC) 

Literature

Structural and biochemical characterization of the type III secretion chaperones CesT and SigE.

Luo, Y., Bertero, M.G., Frey, E.A., Pfuetzner, R.A., Wenk, M.R., Creagh, L., Marcus, S.L., Lim, D., Sicheri, F., Kay, C., Haynes, C., Finlay, B.B., Strynadka, N.C.

(2001) Nat Struct Biol 8: 1031-1036

• PubMed: 11685226 
• DOI: https://doi.org/10.1038/nsb717
• Primary Citation Related Structures: 
  1K3E, 1K3S


• PubMed Abstract: 
  

  Several Gram-negative bacterial pathogens have evolved a type III secretion system to deliver virulence effector proteins directly into eukaryotic cells, a process essential for disease. This specialized secretion process requires customized chaperones specific for particular effector proteins. The crystal structures of the enterohemorrhagic Escherichia coli O157:H7 Tir-specific chaperone CesT and the Salmonella enterica SigD-specific chaperone SigE reveal a common overall fold and formation of homodimers. Site-directed mutagenesis suggests that variable, delocalized hydrophobic surfaces observed on the chaperone homodimers are responsible for specific binding to a particular effector protein. Isothermal titration calorimetry studies of Tir-CesT and enzymatic activity profiles of SigD-SigE indicate that the effector proteins are not globally unfolded in the presence of their cognate chaperones.

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Organizational Affiliation: 
• Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver V6T 1Z3, Canada.

Biological Assembly 1  

Global Symmetry: Cyclic - C2  (Explore in 3D)
Global Stoichiometry: Homo 2-mer - A2 

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

Biological Assembly 2  

Global Symmetry: Cyclic - C2  (Explore in 3D)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 2 generated by PISA (software)

Macromolecule Content 

• Total Structure Weight: 35.39 kDa 
• Atom Count: 2,254 
• Modeled Residue Count: 285 
• Deposited Residue Count: 312 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
CesT	A, B	156	Escherichia coli O157:H7	Mutation(s): 0  Gene Names: cesT
UniProt
Find proteins for P58233 (Escherichia coli O157:H7) Explore P58233  Go to UniProtKB:  P58233

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.80 Å
• R-Value Free:  0.285 (Depositor), 0.285 (DCC) 
• R-Value Work:  0.225 (Depositor), 0.228 (DCC) 

Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 57.586	α = 90
b = 77.856	β = 90
c = 94.176	γ = 90

Software Package:

Software Name	Purpose
SOLVE	phasing
CNS	refinement
DENZO	data reduction
SCALEPACK	data scaling

Structure Validation

Entry History 

Deposition Data

• Released Date: 2001-11-28 
Deposition Author(s): Luo, Y., Bertero, M., Frey, E.A., Pfuetzner, R.A., Wenk, M.R., Creagh, L., Marcus, S.L., Lim, D., Finlay, B.B., Strynadka, N.C.J.

Revision History  

• Version 1.0: 2001-11-28
  Type: Initial release
  
• Version 1.1: 2008-04-27
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance
• Version 1.3: 2016-05-25
  Changes: Source and taxonomy
• Version 1.4: 2024-02-07
  Changes: Data collection, Database references