Nitrosocyanin (NC) is a mononuclear red copper protein
Nitrosocyanin (NC) is isolated from the ammonia oxidizing bacterium Nitrosomonas europaea. Nitrosocyanin exhibits remote sequence homology to classic blue copper proteins; its spectroscopic and electrochemical properties are different. The structure of NC is a trimer of single domain cupredoxins. Nitroscocyanin may mediate electron transfer. It could have a novel role as a nitric oxide dehydrogenase or a nitric oxide reductase in the oxidation of ammonia.
Jiyao W et al.(2023). "The conserved domain database in 2023.",