ADHESIVE PEPTIDES SELECTED BY PHAGE DISPLAY - CHARACTERIZATION, APPLICATIONS AND SIMILARITIES WITH FIBRINOGEN

Phage clones with affinity for polystyrene/polyurethane magnetic parti cles were isolated from a 10-mer peptide display library. Sequence ana lysis revealed that 40 out of 80 clones contained the consensus WXXWXX XW. Some of the selected phages showed high surface activity and adsor bed to plastic surfaces even in the presence of blocking agents or sur factants. Covalent attachment of a synthetic peptide (KG), carrying on e of the the selected sequences, to alkaline phosphatase (AP) or bovin e serum albumin (BSA) enhanced binding of AP to a wide range of materi als and improved the ability of BSA to prevent binding of antibodies a nd phages to polystyrene. Interestingly, the WXXWXXXW motif occurs in the beta- and gamma-chains of the natural ''adhesive'' protein fibrino gen, and a synthetic peptide carrying tile gamma-chain 369-376 sequenc e turned out to have essentially the same binding properties as the KG peptide. Furthermore, adsorption to different types of polystyrene wa s similar for AP carrying either the KG or gamma-chain peptide, intact fibrinogen and plasmin-generated fragment D-1. The latter fragment co ntains two copies of the WXXWXXXW motif but lack the alpha-chain protu berances previously implicated in fibrinogen adsorption. Thus, our stu dy may have revealed a hitherto unknown structural determinant for fib rinogen's adsorptivity, located in the 13-kDa C-terminal region of the gamma-chain.