The polymorphic nature of membrane-active peptides from biophysical and structural investigations.

Membrane-active peptides exhibit a wide variety of biological functions including pore formation, signaling and antimicrobial activities. They are also capable of transporting large cargo such as proteins or nucleic acids across cell membranes. This review summarizes biophysical and structural investigations on hydrophobic, amphipathic and heavily charged peptides that reveal a very dynamic view on their membrane interactions. Individual peptides are able to adopt a variety of different conformations and topology and at the same time exhibit multimodal functionalities. Examples discussed in this paper include peptaibols, magainins, cell penetrating peptides and designed histidine-rich sequences with potent antimicrobial and nucleic acid transfection activities.