Staphylococcus aureus protein A binding to von Willebrand factor A1 domain is mediated by conserved IgG binding regions.
Maghnus O'Seaghdha
Carina J. van Schooten
Steven W. Kerrigan
Jonas Emsley
Gregg J. Silverman
Dermot Cox
Peter J. Lenting
Timothy J. Foster
10779/rcsi.10783811.v1
https://repository.rcsi.com/articles/journal_contribution/Staphylococcus_aureus_protein_A_binding_to_von_Willebrand_factor_A1_domain_is_mediated_by_conserved_IgG_binding_regions_/10783811
<p>Protein A (Spa) is a surface-associated protein of Staphylococcus aureus best known for its ability to bind to the Fc region of IgG. Spa also binds strongly to the Fab region of the immunoglobulins bearing V(H)3 heavy chains and to von Willebrand factor (vWF). Previous studies have suggested that the protein A-vWF interaction is important in S. aureus adherence to platelets under conditions of shear stress. We demonstrate that Spa expression is sufficient for adherence of bacteria to immobilized vWF under low fluid shear. The full length recombinant Ig-binding region of protein A, Spa-EDABC, fused to glutathione-S-transferase (GST), bound recombinant vWF in a dose-dependent and saturable fashion with half maximal binding of about 30 nm in immunosorbent assays. Full length-Spa did not bind recombinant vWF A3 domain but displayed binding to recombinant vWF domains A1 and D'-D3 (half maximal binding at 100 nm and 250 nm, respectively). Each recombinant protein A Ig-binding domain bound to the A1 domain in a similar manner to the full length-Spa molecule (half maximal binding 100 nm). Amino acid substitutions were introduced in the GST-SpaD protein at sites known to be involved in IgG Fc or in V(H)3 Fab binding. Mutants altered in residues that recognized IgG Fc but not those that recognized V(H)3 Fab had reduced binding to vWF A1 and D'-D3. This indicated that both vWF regions recognized a region on helices I and II that overlapped the IgG Fc binding site.</p>
2019-11-22 16:25:59
Amino Acid Sequence
Amino Acid Substitution
Extracellular Matrix Proteins
Glutathione Transferase
Humans
Immunoglobulin G
Models
Molecular
Molecular Sequence Data
Protein Binding
Protein Structure
Tertiary
Recombinant Fusion Proteins
Staphylococcal Protein A
Clinical Pharmacology and Therapeutics