Essential during early vegetative growth (PubMed:24179128). Required for the assembly of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I) (PubMed:24179128). Involved in mitochondrial translation activity (PubMed:24179128). May deliver of one or more Fe-S clusters to complex I subunits (By similarity). Binds 1 [4Fe-4S] cluster. Homozygous mutants are lethal, seeds failing to germinate or arrested seedlings in early growth (PubMed:24179128). Loss of mitochondrial complex I and low levels of a 650-kDa assembly intermediate associated with a reduced mitochondrial translation activity (PubMed:24179128). Heterozygous plants display delayed bolting and flowering, with small and highly branched inflorescences; they also have sporophytic defects in female and male gametophyte development (PubMed:24179128). Belongs to the Mrp/NBP35 ATP-binding proteins family.