PDBsum entry 1ha5

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protein metals Protein-protein interface(s) links
Toxin PDB id
Protein chains
218 a.a. *
_ZN ×4
Waters ×142
* Residue conservation analysis
PDB id:
Name: Toxin
Title: Structural features of a zinc-binding site in the superantigen streptococcal pyrogenic exotoxin a (spea1): implications for mhc class ii recognition.
Structure: Streptococcal pyogenic exotoxin a1. Chain: a, b, c, d. Fragment: residues 33-250. Engineered: yes
Source: Streptococcus pyogenes. Organism_taxid: 1314. Expressed in: escherichia coli. Expression_system_taxid: 511693.
Biol. unit: Monomer (from PDB file)
2.82Å     R-factor:   0.214     R-free:   0.283
Authors: M.D.Baker,D.M.Gutman,A.C.Papageorgiou,C.M.Collins, K.R.Acharya
Key ref: M.Baker et al. (2001). Structural features of a zinc binding site in the superantigen strepococcal pyrogenic exotoxin A (SpeA1): implications for MHC class II recognition. Protein Sci, 10, 1268-1273. PubMed id: 11369867
28-Mar-01     Release date:   03-Apr-02    
Go to PROCHECK summary

Protein chains
P0DJY7  (SPEA_STRPY) -  Exotoxin type A
250 a.a.
218 a.a.*
Key:    Secondary structure  CATH domain
* PDB and UniProt seqs differ at 30 residue positions (black crosses)

 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     extracellular region   1 term 
  Biological process     pathogenesis   1 term 


Protein Sci 10:1268-1273 (2001)
PubMed id: 11369867  
Structural features of a zinc binding site in the superantigen strepococcal pyrogenic exotoxin A (SpeA1): implications for MHC class II recognition.
M.Baker, D.M.Gutman, A.C.Papageorgiou, C.M.Collins, K.R.Acharya.
Streptococcal pyrogenic exotoxin A (SpeA) is produced by Streptococcus pyogenes, and has been associated with severe infections such as scarlet fever and Streptococcal Toxic Shock Syndrome (STSS). In this study, the crystal structure of SpeA1 (the product of speA allele 1) in the presence of 2.5 mM zinc was determined at 2.8 A resolution. The protein crystallizes in the orthorhombic space group P2(1)2(1)2, with four molecules in the crystallographic asymmetric unit. The final structure has a crystallographic R-factor of 21.4% for 7,031 protein atoms, 143 water molecules, and 4 zinc atoms (one zinc atom per molecule). Four protein ligands-Glu 33, Asp 77, His 106, and His 110-form a zinc binding site that is similar to the one observed in a related superantigen, staphylococcoal enterotoxin C2. Mutant toxin forms substituting Ala for each of the zinc binding residues were generated. The affinity of these mutants for zinc ion confirms the composition of this metal binding site. The implications of zinc binding to SpeA1 for MHC class II recognition are explored using a molecular modeling approach. The results indicate that, despite their common overall architecture, superantigens appear to have multiple ways of complex formation with MHC class II molecules.

Literature references that cite this PDB file's key reference

  PubMed id Reference
16113251 D.D.Pless, G.Ruthel, E.K.Reinke, R.G.Ulrich, and S.Bavari (2005).
Persistence of zinc-binding bacterial superantigens at the surface of antigen-presenting cells contributes to the extreme potency of these superantigens as T-cell activators.
  Infect Immun, 73, 5358-5366.  
15049778 K.Petersson, G.Forsberg, and B.Walse (2004).
Interplay between superantigens and immunoreceptors.
  Scand J Immunol, 59, 345-355.  
15295110 M.D.Baker, I.Gendlina, C.M.Collins, and K.R.Acharya (2004).
Crystal structure of a dimeric form of streptococcal pyrogenic exotoxin A (SpeA1).
  Protein Sci, 13, 2285-2290.
PDB code: 1uup
12679262 A.L.Bisno, M.O.Brito, and C.M.Collins (2003).
Molecular basis of group A streptococcal virulence.
  Lancet Infect Dis, 3, 191-200.  
12068802 C.Andersen, E.Koronakis, C.Hughes, and V.Koronakis (2002).
An aspartate ring at the TolC tunnel entrance determines ion selectivity and presents a target for blocking by large cations.
  Mol Microbiol, 44, 1131-1139.  
The most recent references are shown first. Citation data come partly from CiteXplore and partly from an automated harvesting procedure. Note that this is likely to be only a partial list as not all journals are covered by either method. However, we are continually building up the citation data so more and more references will be included with time. Where a reference describes a PDB structure, the PDB code is shown on the right.