Novel synthetic peptides from the C-terminal heparin binding domain of fibronectin with heparin binding activity

To identify a minimal peptide ligand that participates in recognition of heparin, we synthesized peptides extending a 29-kDa fragment in the C-terminal heparin binding domain of fibronectin. We obtained evidence that two peptides (designated D5 and D1) exhibit inhibitory activity on binding of the 29-kDa fragment to heparin-Sepharose CL-6B. In dose inhibitory studies, peptide D5 showed the potent inhibitory activity with IC50 of 210 +/- 37 mu M. A new heparin binding site in the C-terminal heparin binding domain of fibronectin is demonstrated and provides a rationale for understanding the mechanism of cell adhesion and spreading.