Figure 6.

Liquid chromatography–high‐resolution mass spectrometry (LC‐HRMS) analysis of Pseudomonas fluorescens In5 WT, ΔnunF, and complemented mutant. Strains of P. fluorescens In5 WT (a), ΔnunF (b), ΔnunF pHN1270 0 mmol/L IPTG (c), ΔnunF pHN1270 2 mmol/L IPTG (d), ΔnunF pHN1270::nunF 0 mmol/L IPTG (e), and ΔnunF pHN1270::nunF 2 mmol/L IPTG (f) were grown on fifth strength PDA for 48 hr at 20°C. Peptide extraction was performed on agar and biomass using 2‐butanol containing 1% formic acid followed by ultrasonication and evaporation of the organic phase under nitrogen. Samples were resuspended in methanol. LC‐HRMS analysis was performed in triplicate. Extracted ion Chromatograms (EICs) of proton adducts of nunamycin (red) and nunapeptin (blue)