Re-investigation of the HExxH enzyme DarF reveals a dehydrogenation–epoxidation reaction

Darobactin A is a potent Gram-negative antibiotic, but the biosynthesis of its derivative, dehydrodarobactin A, remains unclear. Here, we re-investigated the HExxH enzyme DarF from Pseudoalteromonas luteoviolacea H33 through in vitro characterization and found that it catalyzes a dehydrogenation–epoxidation reaction and detected these darobactin A derivatives in native strains.