Conformational analyses of bacillomycin D, a natural antimicrobial lipopeptide, alone or in interaction with lipid monolayers at the air-water interface

► Bacillomycin D, a natural antimicrobial lipopeptide, has interfacial properties. ► FT-IR spectroscopy and three-dimensional structure modeling show that bacillomycin D contains turns. ► PM-IRRAS spectra show that it keeps its turn conformation at the air-water interface. ► Bacillomycin D has an original behavior toward cholesterol-containing monolayers.