The N-terminal of thrombospondin-1 is essential for coagulase-negative staphylococcal binding

Bacterial binding was studied to determine whether thrombospondin-l (TSP) a cts as a ligand in attachment of coagulase-negative staphylococci (CNS), Tw enty-five of 27 CNS strains bound soluble TSP, Staphylococcus epidermidis J 9P bound I-125-labelled TSP in a dose-dependent manner. Scatchard plot anal ysis of the binding of TSP by strain J9P revealed two Kd values of 6.4 x 10 (-9) h4 and 2.9 x 10(-8)M. The binding structures of strain J9P were sensit ive to protease and were resistant to heat treatment. Unlabelled TSP and re combinant von Willebrand factor inhibited binding of TSP by strain J9P, but other proteins or monosaccharides did not. Heparin inhibited binding of TS P to strain J9P and two other S. epidermidis strains, BD5703 and BD969, Fus ion proteins of the type 1 repeats, type 2 repeats, type 3 repeats and C-te rminal domain of TSP or the synthetic Arg-Gly-Asp peptide did not inhibit b inding of TSP to bacteria. TSP promoted adhesion of S. epidermidis strains when it was immobilised on polymer surfaces. These results indicate that th e specific interaction between CNS and TSP may contribute to bacterial adhe sion on biomaterial surfaces. The N-terminal heparin-binding domain of TSP appears to be the major region for recognition by CNS.