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Molecular structure of staphylococcus and streptococcus superantigens
P M Schlievert1, G A Bohach, D H Ohlendorf
1Department of Microbiology, University of Minnesota Medical School, Minneapolis, 55455-0312, USA.
Journal of Clinical Immunology
|November 1, 1995
Summary
Pyrogenic toxin superantigens from Staphylococcus aureus and streptococci cause severe diseases. Despite sequence differences, structural similarities are hypothesized, with toxic shock syndrome toxin-1 revealing a two-domain structure.
Area of Science:
- Microbiology
- Immunology
- Structural Biology
Background:
- Pyrogenic toxin superantigens are exotoxins produced by Staphylococcus aureus and streptococci.
- These toxins are implicated in toxic shock-like syndromes, allergic, and autoimmune diseases.
- Known superantigens include staphylococcal enterotoxins (SEs), toxic shock syndrome toxin-1 (TSST-1), and streptococcal pyrogenic exotoxins (SPEs).
Purpose of the Study:
- To investigate the sequence and structural similarities among pyrogenic toxin superantigens.
- To characterize the three-dimensional structure of specific superantigens.
Main Methods:
- Nucleotide sequencing of genes encoding superantigens.
- Analysis of sequence similarity between different toxins.
- Determination and analysis of the three-dimensional structures of selected superantigens.
Main Results:
- Sequencing revealed significant similarities between SEB/SEC and SPEA, and between SEA/SED/SEE.
- TSST-1 and SPEB/SPEC showed little sequence similarity to other toxins.
- The three-dimensional structure of TSST-1 was determined, revealing a two-domain (A and B) structure with beta strands forming a claw-like shape.
Conclusions:
- Despite varying primary sequences, pyrogenic toxin superantigens may share conserved three-dimensional structures.
- Structural analysis of TSST-1 provides insights into the molecular basis of superantigen function.
- Further structural studies are warranted to explore the conserved features of this toxin family.