Host-defense antimicrobial peptides: importance of structure for activity.

Antimicrobial peptides are important components of innate immunity in species across the evolutionary scale. Unlike therapeutically used antibiotics, this class of peptides exert their activity by permeabilizing bacterial membranes. Despite the seemingly common mechanism of action, there is considerable variation in their primary structures, length and number of positive charges. Host-defense antimicrobial peptides have been the subject of extensive biophysical studies with a view at delineate structural requirements for activity. In this article, the structures of host defence antibacterial peptides and the structural requirements for activity are reviewed.