Concomitant loss of conformation and superantigenic activity of staphylococcal enterotoxin B deletion mutant proteins
| Autor: | T Marx, Bernhard Fleischer, B Metzroth, M Linnig |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 1993 |
| Předmět: |
DNA
Bacterial Staphylococcus aureus Recombinant Fusion Proteins Immunology Mutant Molecular Sequence Data Biology Microbiology Epitope Enterotoxins Mice Structure-Activity Relationship Mutant protein Animals Amino Acid Sequence Peptide sequence chemistry.chemical_classification Antigens Bacterial Mice Inbred BALB C Base Sequence C-terminus Fusion protein Molecular biology Amino acid Infectious Diseases chemistry Mutation Parasitology Gene Deletion Conformational epitope Research Article |
| Popis: | The T-cell-stimulating activity of staphylococcal enterotoxin B (SEB) is an important factor in the pathogenesis of certain staphylococcal diseases. To investigate the immunologically active domains of the SEB molecule, we have produced truncated fragments of recombinant SEB by C-terminal and N-terminal deletions. The fragments were expressed as fusion proteins with protein A, including a cleavage site to remove the protein A part. Mutant proteins were tested for the ability to stimulate human resting T cells and SEB-reactive T-cell clones. Deletion of only 9 amino acids from the C terminus leads to complete loss of T-cell-stimulating activity. Removing further amino acids from the SEB molecule did not lead to a reexpression of T-cell-mitogenic activity. A mutant protein, however, in which the 9 C-terminal amino acids were replaced with a tail of 68 amino acids encoded by the vector was fully active. Two mutant proteins with N-terminal deletions of 60 and 81 amino acids were inactive as well. A neutralizing monoclonal antibody against a conformational epitope lost binding with all the inactive mutant proteins only, whereas a monoclonal antibody recognizing an epitope involved in emetic activity reacted with all mutant proteins. These results suggest that even small deletions at the C terminus affect the three-dimensional conformation of the SEB molecule. |
| Databáze: | OpenAIRE |
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