Antimicrobial peptides: structure, function and therapeutic potential

Animals and plants protect themselves against invading pathogenic microorganisms by expressing a plethora of cationic antimicrobial peptides on exposed surfaces. These highly charged peptides, some of which are constitutively expressed and present on the cell surface at all times, and some which are expressed following induction by a specific insult, interact with and rapidly eliminate a wide variety of microbial invaders, including Gram-positive and Gram-negative bacteria, fungi and protozoa. Although these peptides are highly toxic to microbial cells, binding to and rapidly lysing the microbe within a few minutes, they are innocuous to host cells at the minimal inhibitory concentration dose range. Highly charged cationic peptides of this class offer the possibility of taking advantage of Nature's natural and highly evolved mechanism to protect an organism from attack by a microorganism, and to develop these novel peptides for biopharmaceutical use against a growing and deadly invasion of novel and rapidly evolving microbes that are resistant to the current antimicrobial armamentaria.