1UNS

IDENTIFICATION OF A SECONDARY ZINC-BINDING SITE IN STAPHYLOCOCCAL ENTEROTOXIN C2: IMPLICATIONS FOR SUPERANTIGEN RECOGNITION

Summary for 1UNS

• Entry DOI: 10.2210/pdb1uns/pdb
• Related: 1CQV 1I4P 1I4Q 1I4R 1I4X 1SE2 1STE
• Descriptor: ENTEROTOXIN TYPE C-2, ZINC ION (3 entities in total)
• Functional Keywords: superantigen, toxin, enterotoxin, zinc-binding site
• Biological source: STAPHYLOCOCCUS AUREUS
• Cellular location: Secreted: P34071
• Total number of polymer chains: 1
• Total formula weight: 27753.78

Authors

Papageorgiou, A.C.,Baker, M.D.,McLeod, J.D.,Goda, S.,Sansom, D.M.,Tranter, H.S.,Acharya, K.R. (deposition date: 2003-09-15, release date: 2003-11-13, Last modification date: 2024-11-06)

Primary citation

Papageorgiou, A.C.,Baker, M.D.,Mcleod, J.D.,Goda, S.,Manzotti, C.N.,Sanson, D.M.,Tranter, H.S.,Acharya, K.R.
Identification of a Secondary Zinc-Binding Site in Staphylococcal Enterotoxin C2: Implications for Superantigen Recognition
J.Biol.Chem., 279:1297-, 2004

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.

PubMed: 14559915
DOI: 10.1074/JBC.M307333200

Experimental method

X-RAY DIFFRACTION (2 Å)