Evidence for three different fibrinogen-binding proteins with unique properties from Staphylococcus aureus strain Newman

Abstract

Binding of extracellular components of Staphylococcus aureus strain Newman to fibrinogen and prothrombin was investigated. Affinity-purified material from fibrinogen- and prothrombin-Sepharose was analysed on immunoblots, and two proteins with coagulase activity were identified. The two coagulases were produced in a sequential manner during staphylococcal growth. An 87 kDa fibrinogen-binding coagulase was produced mainly during the exponential growth phase and was replaced by a 60 kDa fibrinogen- and prothrombin-binding coagulase which was produced mainly during the post-exponential growth phase. In addition, a 19 kDa fibrinogen-binding protein was constitutively produced. Analyses of immunogenic properties and NH2-terminal sequences suggested that the 19, 60 and 87 kDa fibrinogen-binding proteins are not closely related. The NH2-terminal sequence of the 87 kDa protein is identical to a previously described coagulase from Staphylococcus aureus strain 8325-4. The 19 kDa fibrinogen-binding protein, which spontaneously aggregates into dimers and larger molecular weight complexes, had a unique NH2-terminal sequence.