Crystal structure of staphylococcal enterotoxin G (SEG) in complex with a mouse T-cell receptor {beta} chain.

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TitleCrystal structure of staphylococcal enterotoxin G (SEG) in complex with a mouse T-cell receptor {beta} chain.
Publication TypeJournal Article
Year of Publication2011
AuthorsFernández, MM, Cho, S, De Marzi, MC, Kerzic, MC, Robinson, H, Mariuzza, RA, Malchiodi, EL
JournalJ Biol Chem
Date Published2011 Jan 14
KeywordsAnimals, Binding Sites, Cells, Cultured, Crystallography, X-Ray, Enterotoxins, Escherichia coli, Mice, Protein Binding, Protein Structure, Tertiary, Receptors, Antigen, T-Cell, alpha-beta, Staphylococcus aureus, Structure-Activity Relationship, Superantigens

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.

Alternate JournalJ. Biol. Chem.
PubMed ID21059660
PubMed Central IDPMC3020726
Grant ListAI073654 / AI / NIAID NIH HHS / United States
AI36900 / AI / NIAID NIH HHS / United States
TW007972 / TW / FIC NIH HHS / United States