Crystal structure of the streptococcal superantigen SPE-C: dimerization and zinc binding suggest a novel mode of interaction with MHC class II molecules.
Nat Struct Biol
; 4(8): 635-43, 1997 Aug.
Article
en En
| MEDLINE
| ID: mdl-9253413
ABSTRACT
Bacterial superantigens are small proteins that have a very potent stimulatory effect on T lymphocytes through their ability to bind to both MHC class II molecules and T-cell receptors. We have determined the three-dimensional structure of a Streptococcal superantigen, SPE-C, at 2.4 A resolution. The structure shows that SPE-C has the usual superantigen fold, but that the surface that forms a generic, low-affinity MHC-binding site in other superantigens is here used to create a SPE-C dimer. Instead, MHC class II binding occurs through a zinc binding site that is analogous to a similar site in staphylococcal enterotoxin A. Consideration of the SPE-C dimer suggests a novel mechanism for promotion of MHC aggregation and T-cell activation.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Streptococcus pyogenes
/
Proteínas Bacterianas
/
Toxinas Bacterianas
/
Zinc
/
Superantígenos
/
Exotoxinas
/
Proteínas de la Membrana
/
Antígenos Bacterianos
Idioma:
En
Revista:
Nat Struct Biol
Asunto de la revista:
BIOLOGIA MOLECULAR
Año:
1997
Tipo del documento:
Article
País de afiliación:
Nueva Zelanda