Monolayer formation of short helical turn forming peptide derivatives at the air–water and air–solid interfaces

Two tetrapeptide derivatives [peptide A (Boc–Ala–Ile–Ile–Gly–OMe) and peptide B (Boc–Ala–Ile–Leu–Ser–OMe)], that take helical turn conformation in solution, were shown to form monolayer at the air/water interface. Circular dichroism (CD) measurements indicate that peptide A has more helical turn propensity than peptide B in sodium dodecyl sulphate (SDS) micelles. Langmuir–Blodgget film study of peptides A and B suggest that both the peptides form stable monolayer at the air/water interface. Spectroscopic investigations reveal that peptide A forms helical turn assemblage on transferring the film into hydrophilic quartz and hydrophobic ZnSe surfaces. Whereas, peptide B adopts β-sheet structure on hydrophilic surface and a mixture of β-sheet and helical turn conformation on hydrophobic surface.