page_title: Polymyxin
section_title: Chemistry
hierarchical_section_title: Polymyxin / Chemistry
caption_attribution_description: English: Numbers denote sequence of amino acid loading.
context_page_description: Polymyxins are antibiotics. Polymyxins B and E are used in the treatment of Gram-negative bacterial infections. They work mostly by breaking up the bacterial cell membrane. They are part of a broader class of molecules called nonribosomal peptides.
  They are produced in nature by Gram-positive bacteria such as Paenibacillus polymyxa.
context_section_description: Polymyxins are a group of cyclic non-ribosomal polypeptide (NRPs) which are biosynthesized by bacteria belonging to the genus Bacillus, more specifically the subgenus Paenibacillus. Polymyxins consist of 10 amino acid residues, six of which are L-α,γ-diaminobutyric acid (L-DAB). The DAB residues cause polymyxins to have multiple positively charged groups at physiological pH. Seven amino acid residues form the main cyclic component, while the other three extend from one of the cyclic residues as a linear chain terminating in either 6-methyloctanoic acid or 6-methylheptanoic acid at the N-terminus. During cyclization, residue 10 is bound to the bridging residue 4. The amino acid residues and DAB monomers are generally in the L (levo) configuration, however certain strains such as P. polymyxa PKB1 have been observed to incorporate DAB with the D (dextro) configuration at position 3 producing variations of polymyxin B.
  Polymyxin M is also known as "mattacin".
caption: Numbers denote sequence of amino acid loading.
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