Identification of Holrhizins E-Q Reveals the Diversity of Nonribosomal Lipopeptides in Paraburkholderia rhizoxinica.

The products of a nonribosomal peptide synthetase gene, holA, from Paraburkholderia rhizoxinica were investigated using our recently established recombineering technique. Fifteen products, including 13 new linear lipopeptides, holrhizins E-Q (2-8, 10-15), together with the two known holrhizins A and B (1, 9), were detected in the activated mutant, and their structures were identified using HRESIMS, NMR spectroscopy, Marfey's analysis, and feeding experiments with labeled amino acids. The lipohexapeptides 1-3 and 7-14 differ in three amino acid residues and the N-terminal fatty acid chains. The diversity of the holrhizins originates from the substrate flexibility of the A4, A5, and A6 domains as well as the starter C domain in the biosynthetic pathway.