Mapping the energy of superantigen Staphylococcus enterotoxin C3 recognition of an alpha/beta T cell receptor using alanine scanning mutagenesis.

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TitleMapping the energy of superantigen Staphylococcus enterotoxin C3 recognition of an alpha/beta T cell receptor using alanine scanning mutagenesis.
Publication TypeJournal Article
Year of Publication2000
AuthorsChurchill, HR, Andersen, PS, Parke, EA, Mariuzza, RA, Kranz, DM
JournalJ Exp Med
Volume191
Issue5
Pagination835-46
Date Published2000 Mar 6
ISSN0022-1007
KeywordsAlanine, Animals, Binding Sites, Enterotoxins, Humans, Mice, Models, Molecular, Mutagenesis, Protein Binding, Receptors, Antigen, T-Cell, alpha-beta, Staphylococcus aureus, Superantigens, Thermodynamics
Abstract

Binding of the T cell receptor (TCR) to a bacterial superantigen (SAG) results in stimulation of a large population of T cells and subsequent inflammatory reactions. To define the functional contribution of TCR residues to SAG recognition, binding by 24 single-site alanine substitutions in the TCR Vbeta domain to Staphylococcus aureus enterotoxin (SE) C3 was measured, producing an energy map of the TCR-SAG interaction. The results showed that complementarity determining region 2 (CDR2) of the Vbeta contributed the majority of binding energy, whereas hypervariable region 4 (HV4) and framework region 3 (FR3) contributed a minimal amount of energy. The crystal structure of the Vbeta8.2-SEC3 complex suggests that the CDR2 mutations act by disrupting Vbeta main chain interactions with SEC3, perhaps by affecting the conformation of CDR2. The finding that single Vbeta side chain substitutions had significant effects on binding and that other SEC3-reactive Vbeta are diverse at these same positions indicates that SEC3 binds to other TCRs through compensatory mechanisms. Thus, there appears to be strong selective pressure on SAGs to maintain binding to diverse T cells.

Alternate JournalJ. Exp. Med.
PubMed ID10704464
PubMed Central IDPMC2195847
Grant ListAI36900 / AI / NIAID NIH HHS / United States
AI42937 / AI / NIAID NIH HHS / United States
GM55767 / GM / NIGMS NIH HHS / United States