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Multiple specificities of the staphylococcal and streptococcal fibronectin-binding microbial surface components
D Joh1, P Speziale, S Gurusiddappa
1Center for Extracellular Matrix Biology, Institute of Biosciences and Technology, and Department of Biochemistry and Biophysics, Texas A&M University, Houston, USA.
European Journal of Biochemistry
|January 5, 1999
Summary
Pathogenic bacteria use fibronectin (Fn)-binding proteins (MSCRAMMs) to attach. This study reveals MSCRAMMs bind multiple sites on Fn
Area of Science:
- Microbiology
- Structural Biology
- Biochemistry
Background:
- Pathogenic Gram-positive bacteria utilize fibronectin (Fn)-binding microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) for adhesion.
- MSCRAMMs typically possess a ligand-binding domain with multiple repeat motifs, primarily interacting with the N-terminal region of Fn.
Purpose of the Study:
- To investigate the detailed binding interactions between Staphylococcus aureus FnbpA and fibronectin.
- To identify distinct binding sites and motifs within MSCRAMMs responsible for Fn interaction.
Main Methods:
- Dissection of the FnbpA repeat domain using synthetic peptides and recombinant fragments.
- Analysis of binding affinities using fluorescence polarization assays with labeled MSCRAMM peptides and Fn module pairs.
Main Results:
- Staphylococcus aureus FnbpA possesses a secondary ligand-binding domain outside its repeat units.
- Multiple MSCRAMMs bind to various sites on the Fn N-terminus, with discrete motifs mediating these interactions.
- Specific motifs within MSCRAMM repeat units bind to distinct Fn type-I module pairs (e.g., C-terminal motifs to pairs 4-5, N-terminal motifs to pairs 1-2 and 2-3).
Conclusions:
- MSCRAMM binding to fibronectin is more complex than previously thought, involving multiple domains and specific motif-mediated interactions.
- Understanding these interactions is crucial for developing strategies to combat bacterial adhesion and infection.