si_0425 DNA_phosphorothioation NifS-like cysteine desulfurase DndA si_0425 DNA_phosphorothioation DNA sulfur modification protein DndB si_0425 DNA_phosphorothioation 3'-phosphoadenosine 5'-phosphosulfate sulfurtransferase DndC si_0425 DNA_phosphorothioation DNA sulfur modification protein DndD si_0425 DNA_phosphorothioation DNA sulfur modification protein DndE