Corresponds to E. coli MiaB ortholog. Posesses a N-terminal TRAM domain and a C-terminal catalytic radical SAM domain with two [4Fe-4S] clusters coordinated with 3 cysteines and an exchangeable S-AdoMet. Belongs to the same family of methylthiotransferases as B. subtilis MtaB (YqeV), mammalian MtaB (Cdkal1) and protein methylthiotransferase RimO. A MiaB-CDKAL1-like enzyme is present in Archaea, while MiaA/Mod5 is totally absent. Its function is still elusive (2012).