Halogenated Adenine and Adenosine Natural Products in <i>Streptomyces</i> sp. JCM9888

Abstract Ascamycin 1 and dealanylascamycin 2 are adenosine containing nucleoside antibiotics carrying the rare 5’‐ O ‐sulfamoyl ribose motif and a chlorine atom attached to C2 of the adenine ring. Gene knockouts (Δ acmK and Δ acmJ ) in the producing strain, Streptomyces sp. JCM9888, generated mutants that were disabled in the assembly of the sulfamoyl moiety. This resulted in the production of 2‐chloroadenosine 3 and 2‐chloroadenine 4 , indicating that purine halogenation can occur independently of sulfamoylation. Incubations in media enriched in bromide content resulted also in the identification of 2‐bromoadenine 5 , 2‐bromoadenosine 6 and 5′‐ O ‐sulfamoyl‐2‐bromoadenosine 7 .