Antibacterial Mechanisms of Polymyxin and Bacterial Resistance

Figure 1

Representative polymyxin structure and its biosynthesis based on polymyxin B and polymyxin E [9]: (a) chemical structure; (b) polymyxin biosynthesis in Paenibacillus polymyxa; (c) gene cluster for polymyxin biosynthesis. Polymyxin is synthesized by three polymyxin synthetases, PmxA, PmxB, and PmxE, and transported by two membrane transport proteins, PmxC and PmxD. Fatty acid: 6-methyloctanoic acid or isooctanoic acid; Thr: threonine; Phe: phenylalanine; Leu: leucine; Dab: α,γ-diaminobutyric acid. The α and γ refer to the respective –NH₂ involved in peptide linkage.

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