Crystal structure of Staphylococcal Enterotoxin G (SEG) in complex with a mouse T-cell receptor β chain

Marisa M. Fernández, Sangwoo Cho, Mauricio C. De Marzi, Melissa C. Kerzic, Howard Robinson, Roy A. Mariuzza, Emilio L. Malchiodi

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Superantigens (SAgs) are bacterial or viral toxins that bind MHC class II (MHC-II) molecules and T-cell receptor (TCR) in a nonconventional manner, inducing T-cell activation that leads to inflammatory cytokine production, which may result in acute toxic shock. In addition, the emerging threat of purpura fulminans and community-associated meticillin-resistant Staphylococcus aureus emphasizes the importance of a better characterization of SAg binding to their natural ligands that may allow the development of reagents to neutralize their action. The three-dimensional structure of the complex between a mouse TCR β chain (mVβ8.2) and staphylococcal enterotoxin G (SEG) at 2.0 Å resolution revealed a binding site that does not conserve the "hot spots" present in mVβ8.2-SEC2, mVβ8.2-SEC3, mVβ8.2-SEB, and mVβ8.2-SPEA complexes. Analysis of the mVβ8.2-SEG interface allowed us to explain the higher affinity of this complex compared with the others, which may account for the early activation of T-cells bearing mVβ8.2 by SEG. This mode of interaction between SEG and mVβ8.2 could be an adaptive advantage to bestow on the pathogen a faster rate of colonization of the host.

Original languageEnglish (US)
Pages (from-to)1189-1195
Number of pages7
JournalJournal of Biological Chemistry
Issue number2
StatePublished - Jan 14 2011
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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