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Protein A is the von Willebrand factor binding protein on Staphylococcus aureus
J Hartleib1, N Köhler, R B Dickinson
1Departments of Anaesthesiology and Surgical Intensive Care Medicine, Division of Experimental and Clinical Hemostasis, Institute of Medical Microbiology, University of Münster, Münster, Germany.
Blood
|September 9, 2000
Summary
Staphylococcus aureus uses staphylococcal protein A (SPA) to bind to von Willebrand factor (vWF). This interaction is crucial for bacterial adhesion and the development of endovascular infections.
Area of Science:
- Microbiology
- Infectious Diseases
- Biochemistry
Background:
- Endovascular infections caused by Staphylococcus aureus are critical complications.
- Bacterial colonization requires adherence to endothelial surfaces.
- Von Willebrand factor (vWF) mediates platelet adhesion and is implicated in staphylococcal adherence.
Purpose of the Study:
- To identify the specific adhesin responsible for Staphylococcus aureus binding to von Willebrand factor (vWF).
- To elucidate the role of staphylococcal protein A (SPA) in mediating this interaction.
- To understand the contribution of this interaction to the pathogenesis of endovascular staphylococcal disease.
Main Methods:
- Western ligand assays to detect vWF binding to bacterial lysates.
- Surface plasmon resonance to quantify the binding kinetics between vWF and recombinant SPA.
- Flow cytometry to assess vWF binding to S. aureus and inhibition studies.
- Construction and analysis of isogenic Deltaspa mutants.
Main Results:
- Staphylococcal protein A (SPA) was identified as a direct binding partner for vWF.
- SPR analysis showed a high-affinity interaction (Kd = 1.49 x 10(-8) mol/L) between vWF and SPA.
- Deltaspa mutants exhibited significantly reduced vWF binding and adhesion to vWF-coated surfaces.
- Complementation restored the wild-type phenotype, confirming SPA's role.
Conclusions:
- Staphylococcal protein A (SPA) mediates the interaction between Staphylococcus aureus and von Willebrand factor (vWF).
- SPA functions as a novel adhesin contributing to bacterial adhesion in endovascular settings.
- This interaction highlights SPA's significant role in the pathogenesis of endovascular staphylococcal disease.