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Detection of Toxin Translocation into the Host Cytosol by Surface Plasmon Resonance
Published on: January 3, 2012
Clostridium perfringens beta-toxin is sensitive to thiol-group modification but does not require a thiol group for
M Nagahama1, A Kihara, T Miyawaki
1Department of Microbiology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima 770, Japan.
Biochimica Et Biophysica Acta
|June 4, 1999
Summary
Researchers identified key amino acid residues in Clostridium perfringens beta-toxin essential for its lethal activity. Mutating specific sites, particularly near cysteine-265, significantly reduced or eliminated the toxin's potency.
Area of Science:
- Microbiology
- Molecular Biology
- Toxicology
Background:
- Clostridium perfringens beta-toxin is a potent lethal toxin.
- Understanding the molecular basis of beta-toxin's activity is crucial for developing countermeasures.
Purpose of the Study:
- To elucidate the specific amino acid residues critical for the lethal activity of Clostridium perfringens beta-toxin.
- To investigate the role of cysteine-265 and surrounding residues in toxin function.
Main Methods:
- Expression of the beta-toxin gene in Escherichia coli as a glutathione S-transferase (GST) fusion protein.
- Site-directed mutagenesis to alter specific amino acid residues (Cys-265, Tyr-266, Leu-268, Trp-275).
- Biochemical assays to assess the lethal activity of wild-type and mutant toxins.
Main Results:
- Recombinant beta-toxin (r toxin) exhibited biological activities indistinguishable from native beta-toxin (n toxin).
- Mutations at Cys-265, Tyr-266, Leu-268, and Trp-275 significantly reduced or abolished lethal activity.
- Specific chemical modifications of Cys-265 and surrounding residues impacted toxin potency, suggesting a critical active site.
Conclusions:
- The cysteine residue at position 265 and adjacent residues (Tyr-266, Leu-268, Trp-275) are essential for the lethal activity of Clostridium perfringens beta-toxin.
- These findings provide insights into the toxin's mechanism of action and potential targets for inhibition.
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