beta-Neurexin is a ligand for the Staphylococcus aureus MSCRAMM SdrC

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Gram-positive bacteria utilize cell-wall anchored (CWA) proteins for host interactions.
• Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMMs) are a subfamily of CWA proteins with IgG-like folds.
• The specific host ligand for Staphylococcus aureus SdrC, a putative MSCRAMM, was previously unknown.

Purpose of the Study:

• To identify the host ligand for the MSCRAMM SdrC.
• To characterize the binding interaction between SdrC and its identified ligand.
• To elucidate the functional implications of this interaction in host-pathogen dynamics.

Main Methods:

• Phage display peptide library screening to identify SdrC-binding peptides.
• Synthesis and testing of peptides and recombinant proteins for SdrC binding affinity and specificity.
• Bacterial adherence assays using mammalian cells expressing beta-neurexin.

Main Results:

• A peptide sequence within beta-neurexin was identified as a high-affinity, specific binder for SdrC.
• Both synthetic peptides and recombinant beta-neurexin exodomain bound SdrC.
• Expression of SdrC on bacteria significantly increased adherence to beta-neurexin-expressing mammalian cells.

Conclusions:

• Beta-neurexin is a functional ligand for the MSCRAMM SdrC.
• The interaction involves the N-terminal region of beta-neurexin and the N(2)N(3) domain of SdrC.
• This specific host-pathogen interaction has implications for understanding S. aureus pathogenesis.