Multiple states of beta-sheet peptide protegrin in lipid bilayers

The properties of the beta-type antimicrobial peptide protegrin-1 were investigated. Protegrin-1 was analyzed in aligned lipid bilayers using oriented circular dichroism (OCD) and shown to exhibit two significantly distinct OCD spectra as a function of lipid composition, hydration condition and peptide concentration. These two distinct spectra allow the easy determination of the state of the peptide in aligned multilayers. However, the structural basis of the spectra cannot be determined due to lack of a theoretical approach.