Cysteine-stabilized αβ defensins: From a common fold to antibacterial activity

Antimicrobial peptides (AMPs) seem to be promising alternatives to common antibiotics, which are facing increasing bacterial resistance. Among them are the cysteine-stabilized alpha beta defensins. These peptides are small, with a length ranging from 34 to 54 amino acid residues, cysteine-rich and extremely stable, normally composed of an alpha-helix and three beta-strands stabilized by three or four disulfide bonds and commonly found in several organisms. Moreover, animal and plant CS alpha beta defensins present different specificities, the first being mainly active against bacteria and the second against fungi. The role of the CS alpha beta-motif remains unknown, but a common antibacterial mechanism of action, based on the inhibition of the cell-wall formation, has already been observed in some fungal and invertebrate defensins. In this context, the present work aims to group the data about CS alpha beta defensins, highlighting their evolution, conservation, structural characteristics, antibacterial activity and biotechnological perspectives. (C) 2015 Elsevier Inc. All rights reserved.