May play a role in the terminal step of the DOXP/MEP pathway for isoprenoid precursor biosynthesis. H(+) + NADP(+) + 2 reduced [2Fe-2S]-[ferredoxin] = NADPH + 2 oxidized [2Fe-2S]-[ferredoxin] Monomer (PubMed:17258767). Homodimer; disulfide linked (PubMed:17258767, PubMed:19736991). NADP binding accelerates formation of an inactive, disulfide-linked homodimer when the protein is exposed to air for 24 h or more (in vitro); the physiological relevance of this is uncertain (PubMed:17258767). Belongs to the ferredoxin--NADP reductase type 1 family.