title: Identification of a polymyxin synthetase gene cluster of Paenibacillus polymyxa and heterologous expression of the gene in Bacillus subtilis.
abstract: Polymyxin, a long-known peptide antibiotic, has recently been reintroduced in clinical practice because it is sometimes the only available antibiotic for the treatment of multidrug-resistant gram-negative pathogenic bacteria. Lack of information on the biosynthetic genes of polymyxin, however, has limited the study of structure-function relationships and the development of improved polymyxins. During whole genome sequencing of Paenibacillus polymyxa E681, a plant growth-promoting rhizobacterium, we identified a gene cluster encoding polymyxin synthetase. Here, we report the complete sequence of the gene cluster and its function in polymyxin biosynthesis. The gene cluster spanning the 40.6-kb region consists of five open reading frames, designated pmxA, pmxB, pmxC, pmxD, and pmxE. The pmxC and pmxD genes are similar to genes that encode transport proteins, while pmxA, pmxB, and pmxE encode polymyxin synthetases. The insertional disruption of pmxE led to a loss of the ability to produce polymyxin. Introduction of the pmx gene cluster into the amyE locus of the Bacillus subtilis chromosome resulted in the production of polymyxin in the presence of extracellularly added L-2,4-diaminobutyric acid. Taken together, our findings demonstrate that the pmx gene cluster is responsible for polymyxin biosynthesis.
authors.affiliation: Industrial Biotechnology & Bioenergy Research Center, Korea Research Institute of Bioscience and Biotechnology, 111 Gwahangno, Yuseong-gu, Daejeon 305-806, Republic of Korea.
authors.forename: Soo-Keun
authors.initials: SK
authors.lastname: Choi
authors.forename: Soo-Young
authors.initials: SY
authors.lastname: Park
authors.forename: Rumi
authors.initials: R
authors.lastname: Kim
authors.forename: Seong-Bin
authors.initials: SB
authors.lastname: Kim
authors.forename: Choong-Hwan
authors.initials: CH
authors.lastname: Lee
authors.forename: Jihyun F
authors.initials: JF
authors.lastname: Kim
authors.forename: Seung-Hwan
authors.initials: SH
authors.lastname: Park
mesh_terms: D001407:Bacillus / Q000201:enzymology* / Q000235:genetics*; D001412:Bacillus subtilis / Q000235:genetics* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D002853:Chromatography, Liquid; D015964:Gene Expression Regulation, Bacterial; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics*; D016254:Mutagenesis, Insertional; D016366:Open Reading Frames / Q000235:genetics; D016133:Polymerase Chain Reaction; D011113:Polymyxins / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D011113:Polymyxins