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Updated: Jul 23, 2026
Monitoring the Assembly of a Secreted Bacterial Virulence Factor Using Site-specific Crosslinking
Published on: December 17, 2013
Combining molecular modelling and experimental approaches to gain mechanistic insights into the LuxP drug target in
Abdulaziz S Alothaim1, Wardah A Alhoqail2, Muniraj Menakha3
1Department of Biology, College of Science, Majmaah University, Al-Majmaah, Saudi Arabia.
Abstract:
Autoinducer-2 can mediate inter- and intra-species communication signal between bacteria and these signals from AI-2 is noted from limited species of bacteria. In humans, S. pyogenes is a pathogen that causes a wide range of illnesses and can survive in the host system and transmit infection. The process by which S. pyogenes acquires the competence to live and disseminate infection remains unknown. We hypothesized that AI-2 and their receptors would play a significant role during infection, and for that present investigation provides the experimental and molecular insights. In the absence of details about the receptor LuxP and LuxQ, the screening approach provides supporting insights. The evolutionary relationship and similarities of the PBP domain (Spy 1535) and the signal transmission PDZ domain (Spy 1536) were studied in relation to their counterparts in other bacteria. Molecular docking and modeling confirmed the domain-enhanced specificity for AI-2 binding. In vitro studies showed that AI-2, which is present in the cell-free supernatant of S. pyogenes, regulates luminescence in P. luminous and biofilm development in E. coli using the LuxS reporter genes. Examination of S. pyogenes gene expression revealed modulation of virulence genes when the pathogen was exposed to V. harveyi HSL and AI-2. Therefore, S. pyogenes pathogenicity is sequentially regulated by AI-2 it acquires from other commensal bacteria. Overall, this study lays the groundwork for understanding the signalling mechanism from AI-2, which are critical to the pathogenic mechanism of S. pyogenes.Communicated by Ramaswamy H. Sarma.
Insights
Autoinducer-2 (AI-2) signals regulate the pathogenicity of S. pyogenes, a human pathogen. This study reveals AI-2
Area of Science:
- Microbiology
- Molecular Biology
- Bacterial Pathogenesis
Background:
- Autoinducer-2 (AI-2) is a signaling molecule mediating bacterial communication.
- Streptococcus pyogenes (S. pyogenes) is a significant human pathogen, but its infection mechanisms are not fully understood.
- The role of AI-2 in S. pyogenes pathogenicity requires investigation.
Purpose of the Study:
- To investigate the role of AI-2 signaling in S. pyogenes infection.
- To elucidate the molecular mechanisms underlying AI-2 mediated communication in S. pyogenes.
Main Methods:
- Bioinformatic analysis of AI-2 receptor homologs (Spy 1535, Spy 1536) in S. pyogenes.
- Molecular docking and modeling to assess AI-2 binding specificity.
- In vitro assays examining AI-2 effects on reporter gene expression (luminescence, biofilm formation) and S. pyogenes virulence gene expression.
Main Results:
- Structural analysis confirmed potential AI-2 binding domains in S. pyogenes.
- In vitro studies demonstrated AI-2's ability to regulate luminescence in P. luminous and biofilm formation in E. coli.
- Exposure to AI-2 and V. harveyi HSL modulated virulence gene expression in S. pyogenes.
Conclusions:
- S. pyogenes pathogenicity is influenced by AI-2 signaling, potentially acquired from commensal bacteria.
- This study provides molecular insights into AI-2 mediated signaling in a key human pathogen.
- Understanding AI-2 signaling is crucial for deciphering S. pyogenes pathogenic mechanisms.
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