PDBsum entry 1ck1

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protein metals links
Toxin PDB id
Protein chain
239 a.a. *
Waters ×83
* Residue conservation analysis
PDB id:
Name: Toxin
Title: Structure of staphylococcal enterotoxin c3
Structure: Protein (enterotoxin typE C-3). Chain: a
Source: Staphylococcus aureus. Organism_taxid: 1280. Strain: fri-909. Secretion: growing media
Biol. unit: Dimer (from PDB file)
2.60Å     R-factor:   0.162     R-free:   0.233
Authors: Y.-I.Chi,G.A.Bohach,C.V.Stauffacher
Key ref:
Y.I.Chi et al. (2002). Zinc-mediated dimerization and its effect on activity and conformation of staphylococcal enterotoxin type C. J Biol Chem, 277, 22839-22846. PubMed id: 11934896 DOI: 10.1074/jbc.M201932200
26-Apr-99     Release date:   10-Jul-02    
Go to PROCHECK summary

Protein chain
Pfam   ArchSchema ?
Q06535  (Q06535_STAAU) -  Enterotoxin (Fragment)
239 a.a.
239 a.a.*
Key:    PfamA domain  Secondary structure  CATH domain
* PDB and UniProt seqs differ at 3 residue positions (black crosses)

 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     extracellular region   1 term 
  Biological process     pathogenesis   1 term 
  Biochemical function     metal ion binding     1 term  


DOI no: 10.1074/jbc.M201932200 J Biol Chem 277:22839-22846 (2002)
PubMed id: 11934896  
Zinc-mediated dimerization and its effect on activity and conformation of staphylococcal enterotoxin type C.
Y.I.Chi, I.Sadler, L.M.Jablonski, S.D.Callantine, C.F.Deobald, C.V.Stauffacher, G.A.Bohach.
Staphylococcal enterotoxins are superantigen exotoxins that mediate food poisoning and toxic shock syndrome in humans. Despite their structural and functional similarities, superantigens display subtle differences in biological properties and modes of receptor binding as a result of zinc atoms bound differently in their crystal structures. For example, the crystal structures of the staphylococcal enterotoxins in the type C serogroup (SECs) contain a zinc atom coordinated by one aspartate and two histidine residues from one molecule and another aspartate residue from the next molecule, thus forming a dimer. This type of zinc ligation and zinc-mediated dimerization occurs in several SECs, but not in most other staphylococcal enterotoxin serogroups. This prompted us to investigate the potential importance of zinc in SEC-mediated pathogenesis. Site-directed mutagenesis was used to replace SEC zinc binding ligands with alanine. SEC mutants unable to bind zinc did not have major conformational alterations although they failed to form dimers. Zinc binding was not essential for T cell stimulation, emesis, or lethality although in general the mutants were less pyrogenic. Thus the zinc atom in SECs might represent a non-functional heavy atom in an exotoxin group that has diverged from related bacterial toxins containing crucial zinc atoms.
  Selected figure(s)  
Figure 1.
Fig. 1. Ribbon diagrams of the SEC3 structure with the prototype orientation from which two distinct domains are best viewed (A) and with another orientation to show the monomeric zinc binding site (B). The zinc atom and ligands are represented as a ball and stick model. The disulfide bond is also highlighted.
Figure 2.
Fig. 2. Zinc-mediated dimerization. A, a ribbon diagram showing the spatial arrangement of the dimer. The 2-fold axis relating each monomer coincides with the crystallographic axis resulting in one molecule per asymmetric unit. B, closeup of the zinc binding site in a dimeric configuration found in the crystal structure. Asp-9 is from the neighboring molecule.
  The above figures are reprinted by permission from the ASBMB: J Biol Chem (2002, 277, 22839-22846) copyright 2002.  
  Figures were selected by an automated process.  

Literature references that cite this PDB file's key reference

  PubMed id Reference
21255209 S.J.Li, D.L.Hu, E.K.Maina, K.Shinagawa, K.Omoe, and A.Nakane (2011).
Superantigenic activity of toxic shock syndrome toxin-1 is resistant to heating and digestive enzymes.
  J Appl Microbiol, 110, 729-736.  
18506495 J.Hui, Y.Cao, F.Xiao, J.Zhang, H.Li, and F.Hu (2008).
Staphylococcus aureus enterotoxin C2 mutants: biological activity assay in vitro.
  J Ind Microbiol Biotechnol, 35, 975-980.  
15784103 S.Mrabet-Dahbi, K.Breuer, M.Klotz, U.Herz, K.Heeg, T.Werfel, and H.Renz (2005).
Deficiency in immunoglobulin G2 antibodies against staphylococcal enterotoxin C1 defines a subgroup of patients with atopic dermatitis.
  Clin Exp Allergy, 35, 274-281.  
16299279 Z.Jin, G.A.Bohach, J.Shiloach, S.E.Norris, D.I.Freedberg, C.Deobald, B.Coxon, J.B.Robbins, and R.Schneerson (2005).
Conjugates of group A and W135 capsular polysaccharides of neisseria meningitidis bound to recombinant Staphylococcus aureus enterotoxin C1: preparation, physicochemical characterization, and immunological properties in mice.
  Infect Immun, 73, 7887-7893.  
15049778 K.Petersson, G.Forsberg, and B.Walse (2004).
Interplay between superantigens and immunoreceptors.
  Scand J Immunol, 59, 345-355.  
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