reactions. In vitro assays reveal two single‐module non‐ribosomal peptide synthetases (NRPs) that incorporate the β‐keto acid and l‐isoleucine, followed by Dieckmann condensation, to form the quinolone‐γ‐lactam. Notably, the bioconversion from l‐kynurenine to the β‐keto acid is a unique strategy employed by nature to decouple R*‐domain‐containing NRPS from the polyketide synthase (PKS) machinery, expanding