Neither the A- nor B-repeat regions of the fibrinogen-binding protein ofStreptococcus equisubsp.equiare essential for fibrinogen binding

Abstract

The major cell wall-associated protein (FgBP) of Streptococcus equi subsp. equi possesses two internal blocks of repeated sequence (A and B) and binds horse fibrinogen (Fg) avidly through residues located in the N-terminal half of the molecule. In the present study, we investigated the roles of the two repeats blocks in Fg binding through construction of recombinant FgBP proteins containing defined internal deletions of sequence. Ligand binding experiments clearly showed that neither repeat is essential for Fg binding. However, residues within the B repeats seem to play a major role in the aberrant mobility observed for FgBP following sodium dodecyl sulfate polyacrylamide gel electrophoresis.

Protein FOG - a streptococcal inhibitor of neutrophil function

“…equi, in which the C-terminal part contributes to thermal stability of the molecule (Meehan et al, 2002). The same group also showed that neither A nor B repeats are important for binding of FgBp to fibrinogen (Meehan et al, 2000). These domains, however, seem important for conformation and multimerization.…”

The fibrinogen-binding protein (FgBP) of Streptococcus equi subsp. equi additionally binds IgG and contributes to virulence in a mouse model

“…5 ; data not shown). FgBP does not possess the conserved 19 amino acid residue (AHP) sequence which has been implicated in the homophilic protein-protein interactions responsible for formation of S. pyogenes aggregates (Frick et al, 2000) ; however, it can form apparent multimers under certain conditions and the B-repeats of FgBP have been heavily implicated in this process (Meehan et al, 2000b).…”