title: The Three-dimensional structure of a superantigen-like protein, SET3, from a pathogenicity island of the Staphylococcus aureus genome.
abstract: The staphylococcal enterotoxin-like toxins (SETs) are a family of proteins encoded within the Staphylococcus aureus genome that were identified by their similarity to the well described bacterial superantigens. The first crystal structure of a member of the SET family, SET3, has been determined to 1.9 A (R = 0.205, R(free) = 0.240) and reveals a fold characteristic of the superantigen family but with significant differences. The SET proteins are secreted at varying levels by staphylococcal isolates, and seroconversion studies of normal individuals indicate that they are strongly antigenic to humans. Recombinant SETs do not exhibit any of the properties expected of superantigens such as major histocompatibility complex class II binding or broad T-cell activation, suggesting they have an entirely different function. The fact that the whole gene family is clustered within the pathogenicity island SaIn2 of the S. aureus genome suggests that they are involved in host/pathogen interactions.
authors.affiliation: School of Biological Sciences, University of Auckland, Private Bag 92-019 Auckland, New Zealand.
authors.forename: Vickery L
authors.initials: VL
authors.lastname: Arcus
authors.forename: Ries
authors.initials: R
authors.lastname: Langley
authors.forename: Thomas
authors.initials: T
authors.lastname: Proft
authors.forename: John D
authors.initials: JD
authors.lastname: Fraser
authors.forename: Edward N
authors.initials: EN
authors.lastname: Baker
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology; D001665:Binding Sites; D018360:Crystallography, X-Ray; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013211:Staphylococcus aureus / Q000235:genetics* / Q000472:pathogenicity; D018089:Superantigens / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology; D014774:Virulence / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D018089:Superantigens