A novel loop domain in superantigens extends their T cell receptor recognition site.
J Mol Biol
; 371(1): 210-21, 2007 Aug 03.
Article
en En
| MEDLINE
| ID: mdl-17560605
ABSTRACT
Superantigens (SAGs) interact with host immune receptors to induce a massive release of inflammatory cytokines that can lead to toxic shock syndrome and death. Bacterial SAGs can be classified into five distinct evolutionary groups. Group V SAGs are characterized by the alpha3-beta8 loop, a unique approximately 15 amino acid residue extension that is required for optimal T cell activation. Here, we report the X-ray crystal structures of the group V SAG staphylococcal enterotoxin K (SEK) alone and in complex with the TCR hVbeta5.1 domain. SEK adopts a unique TCR binding orientation relative to other SAG-TCR complexes, which results in the alpha3-beta8 loop contacting the apical loop of framework region 4, thereby extending the known TCR recognition site of SAGs. These interactions are absolutely required for TCR binding and T cell activation by SEK, and dictate the TCR Vbeta domain specificity of SEK and other group V SAGs.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Staphylococcus aureus
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Proteínas Bacterianas
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Receptores de Antígenos de Linfocitos T alfa-beta
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Estructura Terciaria de Proteína
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Superantígenos
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Enterotoxinas
Límite:
Humans
Idioma:
En
Revista:
J Mol Biol
Año:
2007
Tipo del documento:
Article
País de afiliación:
Estados Unidos