Isolation and characterisation of a 17-kDa staphylococcal heparin-binding protein with broad specificity

A previous study reported the ability of staphylococci to bind heparin and heparin-dependent host growth factors. The present study isolated and ident ified heparin- and basic fibroblast growth factor (bFGF)-binding surface co mponents of S. epidermidis strain RP12 and S, haemolyticus strain SM 131. T he staphylococcal heparin-binding component(s) were purified by affinity ch romatography on heparin-Sepharose and a major heparin-binding protein, here designated HSP, was identified by immunoblot in these two coagulase-negati ve staphylococcal (CNS) species. The HBP was shown to be acidic with an app roximate pI of 4.6 and a molecular mass around 17 kDa. The binding of hepar in to HBP was inhibited by heparin, fucoidan, pentosan polysulphate and var ious other sulphated polysaccharides, but not by non-sulphated compounds. H owever, the purified HBP from both S, epidermidis and S, haemolyticus revea led broad specificity, and also bound bFGF, thrombospondin, von Willebrand factor and, weakly fibrinogen, The N-terminal sequences of the 17-kDa HBP f rom S, epidermidis and S, haemolyticus showed only limited identity. Compar ison of the first 15 amino acid residues derived from either strain with kn own sequences in the protein databases revealed no close similarities. Take n together, these results suggest that the adhesion of at least some CNS to host sulphated glycosaminoglycans may be mediated by a previously uncharac terised group of surface proteins.