Antimicrobial peptides: New candidates in the fight against bacterial infections

Abstract

Antimicrobial peptides (AMPs) of innate origin are agents of the most ancient form of defense systems. They can be found in a wide variety of species ranging from bacteria through insects to humans. Through the course of evolution, host organisms developed arsenals of AMPs that protect them against a large variety of invading pathogens including both Gram-negative and Gram-positive bacteria. At a time of increasing bacterial resistance, AMPs have been the focus of investigation in a number of laboratories worldwide. Although recent studies show that some of the peptides are likely to have intracellular targets, the vast majority of AMPs appear to act by permeabilization of the bacterial cell membrane. Their activity and selectivity are governed by the physicochemical parameters of the peptide chains as well as the properties of the membrane system itself. In this review, we will summarize some of the recent developments that provide us with a better understanding of the mode of action of this unique family of antibacterial agents. Particular attention will be given to the determinants of AMP-lipid bilayer interactions as well as to the different pore formation mechanisms. The emphasis will be on linear AMPs but representatives of cysteine-bridged AMPs will also be discussed.

The antifungal effect of peptides from hymenoptera venom and their analogs

“…Antimicrobial peptides (AMPs) form the first line of defense against infection [6][7][8][9][10][11][12][13][14][15] and represent a new family of antibiotics that have been extensively studied. The AMPs described in the literature not only have antibacterial activities, but some also efficiently kill fungi, viruses and cancer cells [13][14][15].…”

Effect of Cholesterol on the Phase Change of Lipid Membranes by Antimicrobial Peptides

“…[1][2][3][4][5][6] The antimicrobial peptides lyse the cell membrane by binding on the membrane surface. 7,8 Many factors such as the geometrical structure of the peptide, 9 the surface concentration and charge density of the peptide, 10 and the surface charge density and hydration level of the lipid membranes [11][12][13] are associated with the various membrane-distuption mechanisms, namely the micellization model, the carpet model, the membrane thinning model, the toroidal pore model, and the barrel-stave model. [14][15][16] For example, alamethicin in the fungus Trichoderma viride causes thinning of the lipid membrane at a specific concentration without lysing the membrane.…”

The Design of Bacteria Strain Selective Antimicrobial Peptides Based on the Incorporation of Unnatural Amino Acids

“…AMPs are normally highly positively charged (+3 to +9) small peptides consisting of 5-50 amino acid residues (Hancock, 1998). These peptides are amphipathic molecules with welldefined hydrophobic and hydrophilic regions (Toke, 2005;Zasloff, 2002). As of January 2009, more than 1330 (Wang, Li, & Wang, 2009) natural and synthetic antimicrobial peptides have been characterized.…”