A BBE-like Oxidase, AsmF, Dictates the Formation of Naphthalenic Hydroxyl Groups in Ansaseomycin Biosynthesis.

Ansaseomycins are ansamycin-type natural products produced through expression of the asm gene cluster in a heterologous host. A rare berberine bridge enzyme (BBE) like oxidase, AsmF, is encoded in the asm gene cluster. Deletion of asmF led to the accumulation of a series of structurally diverse compounds, all of which lacked the 23-hydroxyl group in naphthalenic motif. Our work demonstrated that AsmF dictated the formation of the naphthalenic hydroxyl group in ansaseomycin biosynthesis.