has role heterodetic cyclic peptide antimicrobial agent lipopeptide polymyxin CHEBI:59062 Polymyxins are antibiotics with a general structure consisting of a cyclic peptide with a long hydrophobic tail. They disrupt the structure of the bacterial cell membrane by interacting with its phospholipids. Polymyxins are produced by the Gram-positive bacterium Bacillus polymyxa and are selectively toxic for Gram-negative bacteria. chebi_ontology polymixin polymycin polymyxins