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Streptolysin O accelerates the conversion of plasminogen to plasmin
Di Tang1, Hamed Khakzad2, Elisabeth Hjortswang3
1Division of Infection Medicine, Department of Clinical Sciences Lund, Faculty of Medicine, Lund University, Lund, Sweden. di.tang@med.lu.se.
Nature Communications
|November 25, 2024
Summary
Group A Streptococcus exploits plasminogen via streptolysin O, accelerating clot breakdown. This interaction reveals a new mechanism for bacterial spread and survival beyond streptolysin O's known cell-damaging effects.
Area of Science:
- Microbiology
- Biochemistry
- Molecular Biology
Background:
- Group A Streptococcus (GAS) is a human pathogen that utilizes the host's plasminogen-plasmin system for invasion.
- Streptolysin O (SLO) is a key GAS cytolytic toxin, but its role in modulating host fibrinolysis is less understood.
Purpose of the Study:
- To investigate the protein-protein interaction between GAS streptolysin O and human plasminogen.
- To elucidate the structural and functional consequences of this interaction on plasminogen activation.
Main Methods:
- Affinity-enrichment mass spectrometry was employed to identify protein interactions.
- Integrative structural mass spectrometry was used to analyze complex structures and conformational changes.
Main Results:
- A direct interaction between streptolysin O and plasminogen was identified.
- This interaction accelerates plasminogen activation by both host and bacterial activators.
- Structural analysis revealed conformational changes in plasminogen upon binding to SLO, forming a stabilized intermediate.
Conclusions:
- Streptolysin O possesses a moonlighting function in promoting fibrinolysis, aiding GAS dissemination.
- This interaction provides a novel pathomechanistic insight into GAS virulence.
- Targeting this SLO-plasminogen interaction could offer new therapeutic strategies against GAS infections.
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