Antimicrobial peptides play an important role in the innate immunity of multi-cellular organisms. Their activity is directly connected to the details of their nanoscale assembly. Despite their diversity of sequence and structure, antimicrobial peptides share two common features; they are cationic, which allows them to preferentially target the negatively-charged cell membranes of prokaryotes such as bacteria, and they have the ability to assume a three dimensional structure with distinct hydrophobic and hydrophilic faces, called an amphipathic structure. A common class of antimicrobial peptide has the feature that they are unfolded in solution but adopt an amphipathic α-helical structure in the presence of membranes . The formation of an amphipathic structure seems to be required for membrane binding and lytic activity. When the concentration of peptide bound to the membrane reaches a critical concentration, the peptides either insert into the membrane to form pores, or destabilize the membrane by disrupting the membrane curvature. Due to the growing concern of increasing bacterial resistance to antibiotics, the novel mechanism of antimicrobial peptides makes them an interesting alternative to traditional antibiotics.
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