Details

Autor(en) / Beteiligte

• Papageorgiou, Anastassios C.
• Baker, Matthew D.
• McLeod, Julie D.
• Goda, Sayed K.
• Manzotti, Claire N.
• Sansom, David M.
• Tranter, Howard S.
• Acharya, K.Ravi

Titel

Identification of a Secondary Zinc-binding Site in Staphylococcal Enterotoxin C2

Ist Teil von

• The Journal of biological chemistry, 2004-01, Vol.279 (2), p.1297-1303

Ort / Verlag

Elsevier Inc

Erscheinungsjahr

2004

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• 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 (Papageorgiou, A. C., Acharya, K. R., Shapiro, R., Passalacqua, E. F., Brehm, R. D., and Tranter, H. S. (1995) Structure 3, 769-779). Here we present the crystal structure of SEC2 determined to 2.0 Å 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 Å 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.