title: Multiple binding sites in the interaction between an extracellular fibrinogen-binding protein from Staphylococcus aureus and fibrinogen.
abstract: Efb (previously Fib) is a fibrinogen-binding protein secreted by Staphylococcus aureus. It has previously been shown that it plays a role in a wound infection model in the rat and that antibodies against Efb reduce the number of recovered bacteria from the mammary glands in a mouse mastitis model. Efb binds to the alpha-chain of fibrinogen and does not participate in bacterial adherence to fibrinogen. The binding of Efb to fibrinogen is divalent, with one binding site within the two repeat regions in Efb at the N terminus and one binding site at the C terminus. The divalent binding nature leads to precipitation of Efb-fibrinogen complex when the proteins are added to each other at a 1:1 molar ratio. The interaction between Efb and fibrinogen is strongly enhanced by Ca2+ or Zn2+ but not by Mg2.
authors.affiliation: Department of Immunology, Microbiology, Pathology, and Infectious Diseases, Karolinska Institutet, Huddinge University Hospital, F82, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Palma
authors.forename: D
authors.initials: D
authors.lastname: Wade
authors.forename: M
authors.initials: M
authors.lastname: Flock
authors.forename: J I
authors.initials: JI
authors.lastname: Flock
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism*; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005110:Extracellular Space / Q000378:metabolism; D005340:Fibrinogen / Q000378:metabolism*; D051379:Mice; D011233:Precipitin Tests; D011485:Protein Binding; D051381:Rats; D013211:Staphylococcus aureus / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; C089677:Fib protein, Staphylococcus aureus; D005340:Fibrinogen