COMPARISON OF THE BINDING OF ALPHA-HELICAL AND BETA-SHEET PEPTIDES TOA HYDROPHOBIC SURFACE

The induction and stabilisation of secondary structure for a series of amphipathic alpha-helical and beta-sheet peptides upon their binding to lipid-like surfaces has been characterised by reversed phase high-p erformance liquid chromatography (RP-HPLC). In addition, a series of p eptides which have been shown to switch from beta-sheet to alpha-helic al conformation upon transfer from a polar to a non-polar solution env ironment also have been studied. Binding parameters related to the hyd rophobic contact area and affinity for immobilised C18 chains were det ermined at temperatures that ranged from 5 to 85 degrees C, allowing c onformational transitions for the peptides during surface adsorption t o be monitored. The results demonstrated that all peptides which adopt secondary structure in solution also exhibited large changes in their interactive properties. Overall, this study demonstrates that the hyd rophobic face of each amphipathic peptide dominates the binding proces s and that hydrophobic interactions are a major factor controlling the surface induction of secondary structure. (C) Munksgaard 1998.