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A structurally novel staphylococcal protein A from the V8 strain
V Finck-Barbançon1, G Prevost, I Mazurier
1Laboratoire de Toxicologie, Institut de Bactériologie, Faculté de Médecine de l'Université Louis Pasteur, Strasbourg, France.
FEMS Microbiology Letters
|February 1, 1992
Summary
A novel Staphylococcus aureus Protein A variant was identified, lacking an IgG-binding domain and octapeptide repeats. This structurally distinct protein, expressed in E. coli, offers new insights into protein variations.
Area of Science:
- Microbiology
- Molecular Biology
- Immunology
Background:
- Staphylococcus aureus Protein A is a cell wall-anchored protein known for its immunoglobulin G (IgG)-binding properties.
- Variations in Protein A structure can affect its function and interactions.
Purpose of the Study:
- To characterize a structurally novel variant of Staphylococcus aureus Protein A.
- To investigate the genetic basis and structural features of this variant.
Main Methods:
- Cloning and expression of the gene encoding the novel Protein A variant in Escherichia coli.
- Sequence analysis of the expressed protein to determine its structural characteristics.
Main Results:
- The identified Protein A variant has a molecular mass approximately 8000 Da lower than known variants.
- Sequence analysis revealed the absence of a key IgG-binding domain (58 amino acids) and two octapeptide repeat regions.
- The N-terminal sequence analysis suggests methionine as the likely first translated amino acid, located upstream of the previously proposed leucine.
Conclusions:
- The Staphylococcus aureus V8 strain produces a structurally unique Protein A lacking essential functional domains.
- This finding expands the known diversity of Protein A and its potential implications for bacterial-host interactions.