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Published on: March 10, 2021
A High-Homology Region Provides the Possibility of Detecting β-Barrel Pore-Forming Toxins from Various Bacterial
Alexey S Nagel1, Olesya S Vetrova2, Natalia V Rudenko2
1FSBIS FRC Pushchino Scientific Centre of Biological Research, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia.
Abstract:
The pathogenicity of many bacteria, including Bacillus cereus and Staphylococcus aureus, depends on pore-forming toxins (PFTs), which cause the lysis of host cells by forming pores in the membranes of eukaryotic cells. Bioinformatic analysis revealed a region homologous to the Lys171-Gly250 sequence in hemolysin II (HlyII) from B. cereus in over 600 PFTs, which we designated as a "homologous peptide". Three β-barrel PFTs were used for a detailed comparative analysis. Two of them-HlyII and cytotoxin K2 (CytK2)-are synthesized in Bacillus cereus sensu lato; the third, S. aureus α-toxin (Hla), is the most investigated representative of the family. Protein modeling showed certain amino acids of the homologous peptide to be located on the surface of the monomeric forms of these β-barrel PFTs. We obtained monoclonal antibodies against both a cloned homologous peptide and a 14-membered synthetic peptide, DSFNTFYGNQLFMK, as part of the homologous peptide. The HlyII, CytK2, and Hla regions recognized by the obtained antibodies, as well as an antibody capable of suppressing the hemolytic activity of CytK2, were identified in the course of this work. Antibodies capable of recognizing PFTs of various origins can be useful tools for both identification and suppression of the cytolytic activity of PFTs.
Insights
Researchers identified a conserved "homologous peptide" in over 600 pore-forming toxins (PFTs). Monoclonal antibodies targeting this peptide can identify and suppress the cell-lysing activity of bacterial toxins like HlyII, CytK2, and Hla.
Area of Science:
- Microbiology
- Immunology
- Structural Biology
Background:
- Pathogenic bacteria like Bacillus cereus and Staphylococcus aureus utilize pore-forming toxins (PFTs) to lyse host cells.
- These PFTs create pores in eukaryotic cell membranes, contributing significantly to bacterial virulence.
Purpose of the Study:
- To identify conserved regions within PFTs that can be targeted by antibodies.
- To develop broadly applicable antibodies for detecting and neutralizing bacterial PFTs.
Main Methods:
- Bioinformatic analysis to identify homologous sequences in PFTs.
- Protein modeling to visualize the location of conserved regions.
- Generation and characterization of monoclonal antibodies against identified peptide sequences.
Main Results:
- A conserved
- homologous peptide
- ] region was identified in over 600 PFTs.
- Antibodies were successfully generated against this peptide and specific PFTs (HlyII, CytK2, Hla).
- Identified antibody binding sites and demonstrated antibody-mediated suppression of hemolytic activity for CytK2.
Conclusions:
- The identified homologous peptide is a conserved target across diverse PFTs.
- Antibodies targeting this conserved region show potential for broad application in identifying and neutralizing bacterial PFTs.
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