Ceruloplasmin is a multicopper oxidase essential for normal iron homeostasis and copper transport in blood. It also functions in amine oxidation and as an antioxidant preventing free radicals in serum. The protein has 6 cupredoxin domains with six copper centers; three mononuclear sites in domain 2, 4 and 6 and three in the form of trinuclear clusters at the interface of domains 1 and 6. Ceruloplasmin exhibits internal sequence homology that appears to have evolved from the triplication of a sequence unit composed of two tandem cupredoxin domains. This model represents the first cupredoxin domain of ceruloplasmin.
Feature 1: trinuclear Cu binding site [ion binding site], 4 residue positions
Conserved feature residue pattern:H H H H
Evidence:
Structure:1KCW; human ceruloplasmin binds copper at the trinuclear copper site. - View structure with Cn3D
Comment:Trinuclear copper site ligands are typically one or two HxH motifs that can be in the same domain/subunit or in different domains/subunits.
Comment:In the human ceruloplasmin structure, the trinuclear copper binding site is formed by four HxH motifs from two different domains (domains 1 and 6).
Jiyao W et al.(2023). "The conserved domain database in 2023.",