Interferon-inducible iron-sulfur (4FE-4S) cluster-binding antiviral protein which plays a major role in the cell antiviral state induced by type I and type II interferon. Binds 1 [4Fe-4S] cluster. The cluster is coordinated with 3 cysteines and an exchangeable S-adenosyl-L-methionine. Constitutively expressed in spleen, head kidney and trunk kidney. Following viral infection, detected in most organs including liver, gill, intestine, heart, muscle and brain. By interferon type I, type II and LPS. Induced by infection with Infectious spleen and kidney necrosis virus (ISKNV), presumably through type I interferon pathway. Belongs to the radical SAM superfamily. RSAD2 family.