A Fourier transform infrared spectroscopic investigation of hydrophobic peptides in lipid environment: A monolayer study

Abstract

The properties of tripeptides Ala-Ala-Tyr and Leu-Leu-Tyr have been investigated in monolayers by resolution enhanced Fourier transform infrared spetroscopy (FTIR). Interaction with an acidic phospholipid (DPPA) in the mixed monolayer results in changes in the backbone amide groups, whereas neutral phospholipid has no effect on the peptides. From the positions of the amide I bands of the peptides, it can be inferred that the groups are in non-ordered conformation. These observations have important implications for the mechanisms of peptide hormone-receptor interactions and particularly for the role of membrane lipid phase as a biologically important modifier of the hormone conformation.