Download MendeleyIdentification 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: https://doi.org/10.1074/jbc.M307333200
- Primary Citation of Related Structures:
1UNS - 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.
Organizational Affiliation:
Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.
