Acts as a mitochondrial iron-sulfur (Fe-S) cluster assembly factor that facilitates [4Fe-4S] cluster insertion into a subset of mitochondrial proteins such as lipoyl synthase (LS) and succinate dehydrogenase (SDH). Required during the last step of iron-sulfur protein assembly when the iron-sulfur cluster is inserted into the target protein. Probably acts together with the monothiol glutaredoxin grx5. Not required for [2Fe-2S] cluster insertion into mitochondrial proteins (By similarity). May be involved in control of cell division, especially during the resumption from cell cycle arrest (PubMed:12521307). Expression varies throughout the cell cycle, with the highest expression in G1 phase before septation. Expression is also increased after S phase arrest. Expression shows cellular growth phase dependency, with the maximal expression at the diauxic shift. Expression is rapidly decreased when cells approach stationary phase (PubMed:9258332). By UV light (PubMed:12521307, PubMed:9258332). Expressed maximally (3.2-fold) at 4 hours after exposure to 240 J/m(2) of UV light (PubMed:9258332). Leads to delayed spore germination and the unidirectional cell extension is not followed by cell division. Proliferates faster with smaller cell size than the wild-type cell during vegetative growth, but no other significant cellular anomaly, such as defects in septation or cytokinesis are detected. Sensitive to UV light. Shows a normal cell cycle delay after UV irradiation, but displays aberrant septum formation and defects in cytokinesis when released from the UV damage checkpoint. However, chromosome segregation is not affected. Belongs to the BolA/IbaG family.