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Group A streptococcal isolate 64/14 expresses surface plasmin-binding structures in addition to Plr
S S D'Costa1, H Wang, D W Metzger
1Department of Microbiology, Medical College of Ohio, Toledo 43699-0008, USA.
Research in Microbiology
|October 10, 1998
Summary
The recombinant plasmin receptor (Plr) from group A Streptococcus binds plasmin(ogen) and accounts for all surface plasmin-binding properties. However, other bacterial surface structures also bind plasmin.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Group A Streptococcus utilizes surface proteins to bind host plasmin(ogen).
- Understanding these interactions is crucial for pathogen virulence and host immune evasion.
Purpose of the Study:
- To analyze the plasmin(ogen)-binding capabilities of a recombinant plasmin receptor (Plr) from Streptococcus.
- To determine if Plr accounts for all plasmin-binding properties of the bacterium.
Main Methods:
- Functional analysis of recombinant Plr protein.
- Inhibition assays using fluid-phase Plr and monoclonal antibodies.
- Comparison of plasmin binding to recombinant Plr and intact bacteria.
Main Results:
- Recombinant Plr binds Lys-plasmin and Lys-plasminogen effectively, with lower affinity for Glu-plasminogen.
- Plasmin binding to Plr is lysine-inhibitable and not neutralized by alpha 2-antiplasmin.
- Fluid-phase Plr fully inhibits plasmin binding to immobilized Plr and bacteria, but antibodies targeting Plr do not inhibit bacterial plasmin binding.
Conclusions:
- The recombinant plasmin receptor (Plr) from Streptococcus isolate 64/14 possesses significant plasmin(ogen)-binding activity.
- Surface-expressed Plr largely explains the plasmin-binding phenotype of the bacteria.
- Additional, yet unidentified, surface structures on Streptococcus also contribute to plasmin binding.