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M-like, immunoglobulin-binding protein of Streptococcus pyogenes type M15
V Katerov1, C Schalén, A A Totolian
1Institute of Experimental Medicine, Academy of the Medical Sciences, St. Petersburg, Russia.
Abstract:
An M-like protein from Streptococcus pyogenes type M15 strain EF1949 (EMML15) was cloned in Escherichia coli and sequenced. Recombinant EMML15 protein revealed a unique binding pattern for human IgG subclasses not described previously. Comparative analysis of the EMML15 amino acid sequence with those of other M-like proteins of opacity factor positive (OF+) serotypes and protein H, and IgG receptor from OF- serotype M1, showed that IgG-binding proteins with common binding of IgG3 were closely related and distinct from streptococcal IgG receptors not binding IgG3. Thus, the Ig-binding proteins from S. pyogenes were subdivided into two main categories according to binding pattern, protein structure, and gene location.
Insights
Streptococcus pyogenes M-like proteins were categorized based on their unique human IgG subclass binding patterns. This research distinguishes IgG-binding proteins from IgG receptors in M1 strains.
Area of Science:
- Microbiology
- Immunology
- Molecular Biology
Background:
- Streptococcus pyogenes possesses M-like proteins that mediate immune evasion.
- Understanding the interaction of these proteins with human IgG is crucial for vaccine development.
Purpose of the Study:
- To characterize the IgG subclass binding pattern of a novel M-like protein (EMML15) from Streptococcus pyogenes M15.
- To compare EMML15 with other known streptococcal IgG-binding proteins and receptors.
Main Methods:
- Cloning and sequencing of the EMML15 gene from Streptococcus pyogenes EF1949.
- Expression of recombinant EMML15 protein in Escherichia coli.
- Analysis of binding patterns with human IgG subclasses.
Main Results:
- Recombinant EMML15 exhibited a unique binding pattern for human IgG subclasses.
- Comparative analysis revealed two distinct categories of streptococcal IgG-binding proteins based on IgG3 binding.
- Proteins binding IgG3 were closely related and structurally distinct from streptococcal IgG receptors not binding IgG3.
Conclusions:
- Streptococcal Ig-binding proteins can be classified into two main groups based on their IgG subclass binding profiles.
- This classification considers protein structure and gene location, providing insights into their evolution and function.
- The findings aid in understanding Streptococcus pyogenes pathogenesis and developing targeted therapeutics.