Required for the assembly of iron-sulfur (Fe/S) clusters in mitochondria (PubMed:10779357, PubMed:11273703, PubMed:12756240, PubMed:15123690, PubMed:15958384, PubMed:16431909, PubMed:9660806, PubMed:31040179). Assisted by the DnaJ-like co-chaperone JAC1 and the nucleotide exchange factor MGE1, it mediates ATP-dependent Fe-S cluster transfer from the scaffold proteins ISU1/ISU2 to GRX5 (PubMed:11273703, PubMed:12756240, PubMed:15123690, PubMed:15958384, PubMed:16431909, PubMed:31040179, PubMed:26545917, PubMed:23615440). ATP + H2O = ADP + H(+) + phosphate Interacts with the Fe/S cluster assembly proteins ISU1, MGE1, GRX5 and JAC1. Disrupts iron-sulfur (Fe-S) cluster assembly (PubMed:31040179). Normal cytosolic tRNA thiolation (PubMed:31040179). Present with 5550 molecules/cell in log phase SD medium. Belongs to the heat shock protein 70 family.