Purification of active staphylococcal alpha-toxin produced in Bacillus subtilis

Area of Science:

• Microbiology
• Bacterial Pathogenesis
• Protein Expression

Background:

• Staphylococcus aureus is a multidrug-resistant pathogen threatening human and animal health.
• Alpha-toxin (Hla) is a key virulence factor of S. aureus, causing cell lysis by forming pores.
• Existing methods for Hla production may have limitations regarding safety and scalability.

Purpose of the Study:

• To establish a safe and efficient system for the expression and purification of wild-type alpha-toxin (HlaWT).
• To evaluate Bacillus subtilis as a host for producing biologically active extracellular toxins.

Main Methods:

• Construction of a pHT expression vector in B. subtilis with an IPTG-inducible promoter for the hla gene fused to Strep-tag II.
• Induction of Hla expression and analysis using SDS-PAGE and Western blotting.
• Single-step purification using a Strep-Tactin column and confirmation of activity via ELISA and hemolytic assays.

Main Results:

• Successful expression and secretion of extracellular HlaWT in B. subtilis.
• High-purity HlaWT obtained through a single-step purification process.
• Confirmed potent hemolytic activity of the purified HlaWT, indicating biological function.

Conclusions:

• Bacillus subtilis is a suitable and effective host for producing biologically active extracellular toxins like Hla.
• This study provides a scalable, safe, and endotoxin-free platform for HlaWT production.
• The developed system supports research in pathogenesis, diagnostics, immunology, drug screening, and vaccine development.