title: Precursor Amino Acids Inhibit Polymyxin E Biosynthesis in Paenibacillus polymyxa, Probably by Affecting the Expression of Polymyxin E Biosynthesis-Associated Genes.
abstract: Polymyxin E belongs to cationic polypeptide antibiotic bearing four types of direct precursor amino acids including L-2,4-diaminobutyric acid (L-Dab), L-Leu, D-Leu, and L-Thr. The objective of this study is to evaluate the effect of addition of precursor amino acids during fermentation on polymyxin E biosynthesis in Paenibacillus polymyxa. The results showed that, after 35 h fermentation, addition of direct precursor amino acids to certain concentration significantly inhibited polymyxin E production and affected the expression of genes involved in its biosynthesis. L-Dab repressed the expression of polymyxin synthetase genes pmxA and pmxE, as well as 2,4-diaminobutyrate aminotransferase gene ectB; both L-Leu and D-Leu repressed the pmxA expression. In addition, L-Thr affected the expression of not only pmxA, but also regulatory genes spo0A and abrB. As L-Dab precursor, L-Asp repressed the expression of ectB, pmxA, and pmxE. Moreover, it affected the expression of spo0A and abrB. In contrast, L-Phe, a nonprecursor amino acid, had no obvious effect on polymyxin E biosynthesis and those biosynthesis-related genes expression. Taken together, our data demonstrated that addition of precursor amino acids during fermentation will inhibit polymyxin E production probably by affecting the expression of its biosynthesis-related genes.
authors.affiliation: College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310014, China.
authors.forename: Zhiliang
authors.identifier: 0000-0003-4849-7055
authors.initials: Z
authors.lastname: Yu
authors.affiliation: College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310014, China.
authors.forename: Chenglin
authors.initials: C
authors.lastname: Guo
authors.affiliation: College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310014, China.
authors.forename: Juanping
authors.initials: J
authors.lastname: Qiu
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D003091:Colistin / Q000096:biosynthesis* / Q000378:metabolism; D005285:Fermentation; D015870:Gene Expression; D056507:Paenibacillus / Q000235:genetics* / Q000378:metabolism
chemical_list: D000596:Amino Acids; D003091:Colistin