| Type: | Domain | Name: | Flavoprotein pyridine nucleotide cytochrome reductase |
| Description: | Flavoprotein pyridine nucleotide cytochrome reductases [] (FPNCR) catalyse the interchange of reducing equivalents between one-electron carriers and the two-electron-carrying nicotinamide dinucleotides. The enzymes include ferredoxin:NADP+reductases (FNR) [], plant and fungal NAD(P)H:nitrate reductases [, ], NADH:cytochrome b5 reductases [], NADPH:P450 reductases [], NADPH:sulphite reductases [], nitric oxide synthases [], phthalate dioxygenase reductase [], and various other flavoproteins.Despite functional similarities, FPNCRs show no sequence similarity to NADPH:adrenodoxin reductases [], nor to bacterial ferredoxin:NAD+reductases and their homologues []. To date, 3D-structures of 4 members of the family have been solved: Spinacia oleracea(Spinach) ferredoxin:NADP+reductase []; Burkholderia cepacia(Pseudomonas cepacia) phthalate dioxygenase reductase []; the flavoprotein domain of Zea mays(Maize) nitrate reductase []; and Sus scrofa(Pig) NADH:cytochrome b5 reductase []. In all of them, the FAD-binding domain (N-terminal) has the topology of an anti-parallel beta-barrel, while the NAD(P)-binding domain (C-terminal) has the topology of a classical pyridine dinucleotide-binding fold (i.e. a central parallel beta-sheet with 2 helices on each side) []. In spite of such structural similarities, the level of amino acid identity between family members is at or below the limit of significance (e.g., nitrate reductase is only 15% identical to FNR) []. | Short Name: | Flavoprot_Pyr_Nucl_cyt_Rdtase |
