Staphylococcal/Streptococcal toxin, beta-grasp domain (IPR006123)

Short name: Toxin_b-grasp_Staph/Strep

Overlapping homologous superfamilies

Domain relationships



Staphylococcal enterotoxins and streptococcal pyrogenic exotoxins constitute a family of biologically and structurally related toxins produced by Staphylococcus aureus and Streptococcus pyogenes [PMID: 2679358, PMID: 2185544]. These toxins share the ability to bind to the major histocompatibility complex proteins of their hosts. A more distant relative of the family is the S. aureus toxic shock syndrome toxin, which shares only a low level of sequence similarity with this group.

All of these toxins share a similar two-domain fold (N and C-terminal domains) with a long alpha-helix in the middle of the molecule, a characteristic beta-barrel known as the "oligosaccharide/oligonucleotide fold" at the N-terminal domain and a beta-grasp motif at the C-terminal domain. Each superantigen possesses slightly different binding mode(s) when it interacts with MHC class II molecules or the T-cell receptor [PMID: 9514739].

The beta-grasp domain has some structural similarities to the beta-grasp motif present in immunoglobulin-binding domains, ubiquitin, 2Fe-2 S ferredoxin and translation initiation factor 3 as identified by the SCOP database.

GO terms

Biological Process

GO:0009405 pathogenesis

Molecular Function

No terms assigned in this category.

Cellular Component

GO:0005576 extracellular region

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.