Component of the cytosolic iron-sulfur (Fe-S) protein assembly (CIA) machinery. Required for maturation of extramitochondrial Fe-S proteins. Functions as Fe-S scaffold, mediating the de novo assembly of an Fe-S cluster and its transfer to target apoproteins. Essential for embryo development. Binds 3 [4Fe-4S] clusters per homodimer. Contains two stable clusters in the N-termini and one labile, bridging cluster between subunits of the homodimer. Homodimer and homotetramer. Predominantly homodimeric. Although plant and algal NBP35 proteins lack the characteristic CXXC motif in the C-terminus, thought to be required for Fe-S cluster binding, they can bind a [4Fe-4S] cluster in the C-terminus. Also, in this linage, no CFD1 partner protein homolog as found in other eukaryotes can be found. Belongs to the Mrp/NBP35 ATP-binding proteins family. NUBP1/NBP35 subfamily.