1sxt
From Proteopedia
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'''STAPHYLOCOCCAL ENTEROTOXIN TYPE A (SEA) CO-CRYSTALLISED WITH ZINC''' | '''STAPHYLOCOCCAL ENTEROTOXIN TYPE A (SEA) CO-CRYSTALLISED WITH ZINC''' | ||
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[[Category: Staphylococcus aureus]] | [[Category: Staphylococcus aureus]] | ||
[[Category: Sundstrom, S M.]] | [[Category: Sundstrom, S M.]] | ||
| - | [[Category: | + | [[Category: Enterotoxin]] |
| - | [[Category: | + | [[Category: Staphylococcus]] |
| - | [[Category: | + | [[Category: Superantigen]] |
| - | [[Category: | + | [[Category: Toxin]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 09:15:38 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 06:15, 3 May 2008
STAPHYLOCOCCAL ENTEROTOXIN TYPE A (SEA) CO-CRYSTALLISED WITH ZINC
Overview
Superantigens form complexes with major histocompatibility complex (MHC) class II molecules and T-cell receptors resulting in extremely strong immunostimulatory properties. Staphylococcus aureus enterotoxin A (SEA) belongs to a subgroup of the staphylococcal superantigens that utilizes Zn2+ in the high affinity interaction with MHC class II molecules. A high affinity metal binding site was described previously in SEA co-crystallized with Cd2+ in which the metal ion was octahedrally co-ordinated, involving the N-terminal serine. We have now co-crystallized SEA with its native co-factor Zn2+ and determined its crystal structure at 2.7 A resolution. As expected for a Zn2+ ion, the co-ordination was found to be tetrahedral. Three of the ligands are located on the SEA surface on a C-terminal domain beta-sheet, while the fourth varies with the conditions. Further analysis of the zinc binding event was performed using titration microcalorimetry, which showed that SEA binds Zn2+ with an affinity of KD = 0.3 microM in an entropy driven process. The differential Zn2+ co-ordination observed here has implications for the mechanism of the SEA-MHC class II interaction.
About this Structure
1SXT is a Single protein structure of sequence from Staphylococcus aureus. Full crystallographic information is available from OCA.
Reference
The Co-crystal structure of staphylococcal enterotoxin type A with Zn2+ at 2.7 A resolution. Implications for major histocompatibility complex class II binding., Sundstrom M, Hallen D, Svensson A, Schad E, Dohlsten M, Abrahmsen L, J Biol Chem. 1996 Dec 13;271(50):32212-6. PMID:8943278 Page seeded by OCA on Sat May 3 09:15:38 2008
