PMID- 7582894
OWN - NLM
STAT- MEDLINE
DCOM- 19951207
LR  - 20190913
IS  - 0969-2126 (Print)
IS  - 0969-2126 (Linking)
VI  - 3
IP  - 8
DP  - 1995 Aug 15
TI  - Crystal structure of the superantigen enterotoxin C2 from Staphylococcus aureus 
      reveals a zinc-binding site.
PG  - 769-79
AB  - BACKGROUND: Staphylococcus aureus enterotoxin C2 (SEC2) belongs to a family of 
      proteins, termed 'superantigens', that form complexes with class II MHC molecules 
      enabling them to activate a substantial number of T cells. Although superantigens 
      seem to act by a common mechanism, they vary in many of their specific 
      interactions and biological properties. Comparison of the structure of SEC2 with 
      those of two other superantigens--staphylococcal enterotoxin B (SEB) and toxic 
      shock syndrome toxin-1 (TSST-1)--may provide insight into their mode of action. 
      RESULTS: The crystal structure of SEC2 has been determined at 2.0 A resolution. 
      The overall topology of the molecule resembles that of SEB and TSST-1, and the 
      regions corresponding to the MHC class II and T-cell receptor binding sites on 
      SEB are quite similar in SEC2. A unique feature of SEC2 is the presence of a zinc 
      ion located in a solvent-exposed region at the interface between the two domains 
      of the molecule. The zinc ion is coordinated to Asp83, His118, His122 and Asp9* 
      (from the neighbouring molecule in the crystal lattice). Atomic absorption 
      spectrometry demonstrates that zinc is also bound to SEC2 in solution. 
      CONCLUSIONS: SEC2 appears to be capable of binding to MHC class II molecules in 
      much the same manner as SEB. However, structure-function studies have suggested 
      an alternative binding mode that involves a different site on the toxin. The zinc 
      ion of SEC2 lies within this region and thus may be important for complex 
      formation, for example by acting as a bridge between the two molecules. Other 
      possible roles for the metal cation, including a catalytic one, are also 
      considered.
FAU - Papageorgiou, A C
AU  - Papageorgiou AC
AD  - School of Biology and Biochemistry, University of Bath, Claverton Down, UK.
FAU - Acharya, K R
AU  - Acharya KR
FAU - Shapiro, R
AU  - Shapiro R
FAU - Passalacqua, E F
AU  - Passalacqua EF
FAU - Brehm, R D
AU  - Brehm RD
FAU - Tranter, H S
AU  - Tranter HS
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Structure
JT  - Structure (London, England : 1993)
JID - 101087697
RN  - 0 (Bacterial Toxins)
RN  - 0 (Enterotoxins)
RN  - 0 (Superantigens)
RN  - 0 (enterotoxin F, Staphylococcal)
RN  - 39424-53-8 (enterotoxin B, staphylococcal)
RN  - 39424-54-9 (enterotoxin C, staphylococcal)
RN  - J41CSQ7QDS (Zinc)
SB  - IM
MH  - Amino Acid Sequence
MH  - *Bacterial Toxins
MH  - Binding Sites
MH  - Crystallography, X-Ray/methods
MH  - Enterotoxins/*chemistry/metabolism
MH  - Models, Molecular
MH  - Molecular Sequence Data
MH  - *Protein Structure, Secondary
MH  - Sequence Homology, Amino Acid
MH  - *Staphylococcus aureus/immunology
MH  - Superantigens/*chemistry/metabolism
MH  - Zinc/*metabolism
EDAT- 1995/08/15 00:00
MHDA- 1995/08/15 00:01
CRDT- 1995/08/15 00:00
PHST- 1995/08/15 00:00 [pubmed]
PHST- 1995/08/15 00:01 [medline]
PHST- 1995/08/15 00:00 [entrez]
AID - S0969-2126(01)00212-X [pii]
AID - 10.1016/s0969-2126(01)00212-x [doi]
PST - ppublish
SO  - Structure. 1995 Aug 15;3(8):769-79. doi: 10.1016/s0969-2126(01)00212-x.