Requires Mg2+. The enzyme, characterized from the bacterium Staphylococcus aureus, catalyses the last step in the biosynthesis of the siderophore staphyloferrin B. It belongs to a class of siderophore synthases known as type B nonribosomal peptide synthase-independent synthases (NIS). Type B NIS enzymes recognize the delta-acid group of 2-oxoglutarate. The enzyme forms a 2-oxoglutarate adenylate intermediate prior to ligation.