Antimicrobial peptides and peptaibols, substitutes for conventional antibiotics.

In this review, the antimicrobial properties of a number of peptides are described. We first deal with helical linear peptides such as the well-known gramicidin, magainins, melittin, and other less well-known or more recently discovered peptides. Then, beta-sheet peptides (defensins isolated from insects and also from mammalian tissues) and cyclic peptides like amphotericin B are described before the properties of peptaibols (containing the non-coded amino acid Aib) are discussed. Alamethicin remains the prototype of this class and its biophysical properties (mostly focussing on channel- or pore-formation in planar lipid bilayers) were and are still intensively studied. On the whole, we show how biophysical studies can explain the antimicrobial action of this ever expanding family of peptides.