The Alignment of Membrane-Active Peptides Depends on the Lipid Phase State as Viewed by solid state 19F-NMR

Amphipathic membrane-active peptides (antimicrobial, hemolytic, cell-penetrating, fusogenic, etc.) achieve their functions by distinct interaction with lipid bilayers. Some typical structural modes are described in terms of models like the “barrel stave”, “toroidal pore”, “carpet” etc. These models are related to the alignment states of the peptides in the lipid bilayers (surface bound “S-state”, inserted “I-state” or tilted “T-state”), which can be readily characterized by solid state NMR. When determining such alignment, factors like peptide/lipid ratio, charge of the bilayer surface, thickness of the bilayer core, presence of cholesterol, and humidity are typically investigated. Yet, the…