THE BINDING ABILITY TO MATRIX PROTEINS AND THE INHIBITORY EFFECTS ON CELL-ADHESION OF SYNTHETIC PEPTIDES DERIVED FROM A CONSERVED SEQUENCE OF INTEGRINS

The beta peptide (113-125), derived from a conserved sequence of the b eta subunit of integrins, was synthesized to investigate its adhesive properties to matrix proteins and the effects on cell adhesion to immo bilized fibronectin, In this study, we observed that the biotinylated beta peptide was able to bind efficiently to immobilized fibronectin, fibrinogen, collagen Type I and vitronectin with different degrees of affinity, It was also demonstrated that biotinylated fibronectin or fi brinogen could bind to the coated beta peptide, This kind of binding, which might be non-covalent linkage, was partially blocked by coincuba tion with the peptide GRGDS or EDTA, but not by SDGRG. Cell adhesion e xperiments were performed to study the effect of the beta peptide, The data showed that the beta peptide partially inhibited both fibroblast L929 and MC3T3-E1 osteoblastic cells from adhering to immobilized fib ronectin in a dosage-dependent manner, In the presence of 100 mu M con centration of the beta peptide, the inhibition rate of cell adhesion w as 34% for fibroblast L929 cells and 54.1% for MC 3T3-E1 osteoblastic cells, This research suggests that the beta peptide might act independ ently as an adhesive region of the beta subunit of integrins and may o ccupy the cell-binding site within fibronectin.