Dermaseptins are antimicrobial peptides, strings of amino acids, or proteins, of various sizes and shapes. Dermaseptins were isolated from frog skin. Dermaseptin is a crucial part of the frog's immune system, inhibiting the growth of bacteria, protozoa and fungi. Dermaseptins are cationic (positively charged) and 27-34 residues in length. Dermaseptins adopt a largely K-helical conformation when binding to membranes. Like other antimicrobial peptides, dermaseptin is membrane-perturbing; however, unlike other antimicrobial peptides, dermaseptin rests on the surface of the bacterial membrane and does not insert.