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Binding of heparan sulfate to Staphylococcus aureus
O D Liang1, F Ascencio, L A Fransson
1Department of Medical Microbiology, University of Lund, Sweden.
Infection and Immunity
|March 1, 1992
Summary
Staphylococcus aureus surface proteins bind heparan sulfate, a key interaction identified through protein isolation and characterization. This binding is crucial for understanding bacterial adhesion mechanisms.
Area of Science:
- Microbiology
- Biochemistry
- Glycobiology
Background:
- Staphylococcus aureus possesses surface proteins that interact with host cell components.
- Heparan sulfate is a glycosaminoglycan found on host cell surfaces, potentially mediating bacterial interactions.
Purpose of the Study:
- To identify and characterize Staphylococcus aureus surface proteins that bind heparan sulfate.
- To elucidate the molecular basis of heparan sulfate-S. aureus interactions.
Main Methods:
- Radioligand binding assays using 125I-heparan sulfate.
- Enzymatic and chemical treatments of bacterial cells.
- Scatchard plot analysis for binding affinity.
- Affinity chromatography using heparin-Sepharose for protein isolation.
- Protein identification via N-terminal sequencing.
Main Results:
- Heparan sulfate binding to S. aureus was time-dependent, saturable, pH, and ionic strength-influenced.
- Proteolytic enzyme treatments (pronase E, proteinase K, pepsin, chymotrypsin) reduced binding, indicating proteinaceous nature of binding sites.
- Scatchard analysis revealed low-affinity binding sites (Kd = 3 x 10(-5) M).
- Two proteins (approximately 66 and 60 kDa) capable of binding heparan sulfate were isolated and partially sequenced.
Conclusions:
- Staphylococcus aureus cell surface harbors proteins that specifically bind heparan sulfate.
- The identified proteins are potential mediators of S. aureus adhesion to host tissues expressing heparan sulfate.
- Further characterization of these proteins may reveal novel therapeutic targets for S. aureus infections.