FAD_NAD(P)H binding domain of flavohemoglobin. Flavohemoglobins have a globin domain containing a B-type heme fused with a ferredoxin reductase-like FAD/NAD-binding domain. Flavohemoglobins detoxify nitric oxide (NO) via an NO dioxygenase reaction. The hemoglobin domain adopts a globin fold with an embedded heme molecule. Flavohemoglobins also have a C-terminal reductase domain with bindiing sites for FAD and NAD(P)H. This domain catalyzes the conversion of NO + O2 + NAD(P)H to NO3- + NAD(P)+. Instead of the oxygen transport function of hemoglobins, flavohemoglobins seem to act in NO dioxygenation and NO signalling.