Structural features of helical antimicrobial peptides: their potential to modulate activity on model membranes and biological cells

Antibacterial, membrane-lytic peptides belong to the innate immune system a nd host defense mechanism of a multitude of animals and plants, The largest group of peptide antibiotics comprises peptides which fold into an amphipa thic alpha-helical conformation when interacting with the target. The activ ity of these peptides is thought to be determined by global structural para meters rather than by the specific amino acid sequence. This review is conc erned with the influence of structural parameters, such as peptide helicity , hydrophobicity, hydrophobic moment, peptide charge and the size of the hy drophobic/hydrophilic domain, on membrane activity and selectivity. The pot ential of these parameters to increase the antibacterial activity and to im prove the prokaryotic selectivity of natural and model peptides is assessed . Furthermore, biophysical studies are summarized which elucidated the mole cular basis for activity and selectivity modulations on the level of model membranes. Finally, the knowledge about the role of peptide structural para meters is applied to understand the different activity spectra of natural m embrane-lytic peptides, (C) 1999 Elsevier Science B.V, All rights reserved.