Catalyzes the formation of 3 thioether bonds during production of the sactipeptide subtilosin from SboA. In vitro the thioether bonds cannot be made in the absence of the SboA propeptide, suggesting this is the first reaction in subtilosin maturation (PubMed:22366720). In vitro, in the absence of a second substrate, cleaves S-adenosyl-L-methionine into Met and 5'-dA (PubMed:22366720). Binds 2 [4Fe-4S] clusters. One cluster is coordinated with 3 cysteines and an exchangeable S-adenosyl-L-methionine, the other is coordinated via 3 cysteines and maybe direct contact with the SboA precursor. Transcription is highly induced by oxygen limitation and is under dual and independent control of Spo0A-AbrB and ResDE.