1BXT

STREPTOCOCCAL SUPERANTIGEN (SSA) FROM STREPTOCOCCUS PYOGENES


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.263 
  • R-Value Work: 0.237 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural basis for HLA-DQ binding by the streptococcal superantigen SSA.

Sundberg, E.Jardetzky, T.S.

(1999) Nat.Struct.Mol.Biol. 6: 123-129

  • DOI: 10.1038/5809

  • PubMed Abstract: 
  • Streptococcal superantigen (SSA) is a 28,000 Mr toxin originally isolated from a pathogenic strain of Streptococcus pyogenes that has 60% sequence identity with staphylococcal enterotoxin B (SEB). SSA and SEB, however, do not compete for binding on t ...

    Streptococcal superantigen (SSA) is a 28,000 Mr toxin originally isolated from a pathogenic strain of Streptococcus pyogenes that has 60% sequence identity with staphylococcal enterotoxin B (SEB). SSA and SEB, however, do not compete for binding on the surfaces of cells expressing MHC class II molecules. This behavior had been ascribed to SSA and SEB binding to distinct sites on, or different subsets of, HLA-DR molecules. Here we demonstrate that SSA binds predominantly to HLA-DQ, rather than to HLA-DR molecules, and present the crystal structure of SSA at 1.85 A resolution. These data provide a structural basis for interpreting the interaction of SSA with HLA-DQ molecules as well as a foundation for understanding bacterial superantigen affinities for distinct MHC isotypes.


    Organizational Affiliation

    Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, Illinois 60208, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
PROTEIN (STREPTOCOCCAL SUPERANTIGEN)
A, B
234Streptococcus pyogenesMutation(s): 0 
Gene Names: SSA
Find proteins for Q54971 (Streptococcus pyogenes)
Go to UniProtKB:  Q54971
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.263 
  • R-Value Work: 0.237 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 81.900α = 90.00
b = 84.550β = 90.00
c = 144.010γ = 90.00
Software Package:
Software NamePurpose
X-PLORrefinement
DENZOdata reduction
SCALEPACKdata scaling
AMoREphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1998-10-14
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance