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Super-Resolution Imaging of Bacterial Secreted Proteins Using Genetic Code Expansion
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Two common structural motifs for TCR recognition by staphylococcal enterotoxins
Karin E J Rödström1, Paulina Regenthal1, Christopher Bahl2
1Department of Experimental Medical Science, Lund University, BMC C13, 22 184, Lund, Sweden.
Scientific Reports
|May 17, 2016
Summary
Staphylococcal enterotoxins (SEs) are dangerous toxins. Researchers identified common binding areas on T cell receptors (TCRs) for multiple SEs, enabling the design of broad-acting antagonists.
Area of Science:
- Immunology and Microbiology
- Structural Biology
- Biochemistry
Background:
- Superantigens, such as staphylococcal enterotoxins (SEs), are potent toxins produced by Staphylococcus aureus.
- These toxins activate T cells by cross-linking the T cell receptor (TCR) and MHC class II molecules, leading to massive immune responses and disease.
- Due to their stability and toxicity, SEs pose significant bioterrorism risks, necessitating the development of effective countermeasures.
Purpose of the Study:
- To investigate the structural basis of T cell receptor (TCR) binding by staphylococcal enterotoxins (SEs).
- To identify conserved regions involved in SE-TCR interactions for the design of broad-spectrum antagonists.
- To provide insights for developing countermeasures against SE-mediated bioterrorism and food poisoning.
Main Methods:
- Determined crystal structures of staphylococcal enterotoxin A (SEA) and staphylococcal enterotoxin E (SEE) in complex with a T cell receptor (TCR).
- Performed computational alanine-scanning mutagenesis on SEA, staphylococcal enterotoxin B (SEB), staphylococcal enterotoxin C3 (SEC3), SEE, and staphylococcal enterotoxin H (SEH).
- Analyzed structural data and mutagenesis results to identify common TCR-binding interfaces across multiple SEs.
Main Results:
- Presented crystal structures revealing the molecular interactions between SEA-TCR and SEE-TCR complexes.
- Identified two common surface areas critical for the general binding of various staphylococcal enterotoxins to the T cell receptor.
- Computational mutagenesis confirmed the significance of these identified regions in mediating TCR interactions for multiple SEs.
Conclusions:
- The identified conserved TCR-binding regions provide a structural basis for understanding superantigen-mediated T cell activation.
- These findings pave the way for designing single antagonist molecules effective against a range of staphylococcal enterotoxins.
- Development of such broad-acting antagonists could serve as crucial countermeasures against bioterrorism and SE-induced diseases.
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