Biological Assembly 1  

 3D View: Structure | Ligand Interaction

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Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A 

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

Macromolecule Content

• Total Structure Weight: 27753.79 
• Atom Count: 1895 
• Residue Count: 239 
• Unique protein chains: 1

1UNS

IDENTIFICATION OF A SECONDARY ZINC-BINDING SITE IN STAPHYLOCOCCAL ENTEROTOXIN C2: IMPLICATIONS FOR SUPERANTIGEN RECOGNITION

• DOI: 10.2210/pdb1UNS/pdb

• Classification: TOXIN
• Organism(s): Staphylococcus aureus


• Deposited: 2003-09-15 Released: 2003-11-13 
• Deposition Author(s): Papageorgiou, A.C., Baker, M.D., McLeod, J.D., Goda, S., Sansom, D.M., Tranter, H.S., Acharya, K.R.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2 Å
• R-Value Free: 0.225 
• R-Value Work: 0.198 

Literature

Identification of a Secondary Zinc-Binding Site in Staphylococcal Enterotoxin C2: Implications for Superantigen Recognition

Papageorgiou, A.C., Baker, M.D., Mcleod, J.D., Goda, S., Manzotti, C.N., Sanson, D.M., Tranter, H.S., Acharya, K.R.

(2004) J.Biol.Chem. 279: 1297

• PubMed: 14559915 
• DOI: 10.1074/jbc.M307333200


• PubMed Abstract: 
  

The previously determined crystal structure of the superantigen staphylococcal enterotoxin C2 (SEC2) showed binding of a single zinc ion located between the N- and C-terminal domains. Here we present the crystal structure of SEC2 determined to 2.0 A resolution in the presence of additional zinc. The structure revealed the presence of a secondary zinc-binding site close to the major histocompatibility complex (MHC)-binding site of the toxin and some 28 A away from the primary zinc-binding site of the toxin found in previous studies. T cell stimulation assays showed that varying the concentration of zinc ions present affected the activity of the toxin and we observed that high zinc concentrations considerably inhibited T cell responses. This indicates that SEC2 may have multiple modes of interaction with the immune system that are dependent on serum zinc levels. The potential role of the secondary zinc-binding site and that of the primary one in the formation of the TCR.SEC2.MHC complex are considered, and the possibility that zinc may regulate the activity of SEC2 as a toxin facilitating different T cell responses is discussed.

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Related Citations: 

• Crystallization and Preliminary X-Ray Analysis of a Microbial Superantigen Staphylococcal Enterotoxin C2
  Passalacqua, E.F.,Brehm, R.D.,Acharya, K.R.,Tranter, H.S.
  (1993) J.Mol.Biol. 233: 170
• Molecular Topology is Important for the Function of Staphylococcal Superantigens
  Tranter, H.,Brehm, R.D.,Acharya, K.R.
  (1995) Bacterial Superantigens: Structure, Function and Therapeutic Potential --: 5
• Structural Basis of Superantigen Action Inferred from Crystal Structure of Toxic-Shock Syndrome Toxin-1
  Acharya, K.R.,Passalacqua, E.F.,Jones, E.Y.,Harlos, K.,Stuart, D.I.,Brehm, R.D.,Tranter, H.S.
  (1994) Nature 367: 94
• Structure of the Superantigen Enterotoxin C2 from Staphylococcus Aureus Reveals a Zinc-Binding Site
  Papageorgiou, A.C.,Acharya, K.R.,Shapiro, R.,Passalacqua, E.F.,Brehm, R.D.,Tranter, H.S.
  (1995) Structure 3: 769




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Organizational Affiliation: 

Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.

Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
ENTEROTOXIN TYPE C-2	A	239	Staphylococcus aureus	Mutation(s): 0  Gene Names: entC2
Find proteins for P34071 (Staphylococcus aureus) Go to UniProtKB:  P34071

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram & Interactions
ZN	A	ZINC ION Zn PTFCDOFLOPIGGS-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2 Å
• R-Value Free: 0.225 
• R-Value Work: 0.198 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length (Å)	Angle (°)
a = 42.500	α = 90.00
b = 44.540	β = 90.00
c = 131.650	γ = 90.00

Software Package:

Software Name	Purpose
CNS	refinement
SCALEPACK	data scaling
DENZO	data reduction

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2003-09-15 
• Released Date: 2003-11-13 
• Deposition Author(s): Papageorgiou, A.C., Baker, M.D., McLeod, J.D., Goda, S., Sansom, D.M., Tranter, H.S., Acharya, K.R.

Revision History 

• Version 1.0: 2003-11-13
  Type: Initial release
• Version 1.1: 2011-05-08
  Type: Version format compliance
• Version 1.2: 2011-07-13
  Type: Version format compliance