The second cupredoxin domain of a multicopper oxidase McoC and similar proteins
This family includes bacterial multicopper oxidases (MCOs) represented by McoC from the pathogenic bacterium Campylobacter jejuni. McoC is a periplasmic MCO, which has been characterized to be associated with copper homeostasis. McoC may also function to protect against oxidative stress as it may convert metallic ions into their less toxic form. MCOs are multi-domain enzymes that are able to couple oxidation of substrates with the reduction of dioxygen to water. These MCOs are capable of oxidizing a vast range of substrates, varying from aromatic to inorganic compounds such as metals. They are composed of three cupredoxin domains that include one mononuclear and one trinuclear copper center. The copper ions are bound in several sites: Type 1, Type 2, and/or Type 3. The ensemble of types 2 and 3 copper is called a trinuclear cluster. MCOs oxidize their substrate by accepting electrons at a mononuclear copper center and transferring them to the active site trinuclear copper center. The cupredoxin domain 2 of 3-domain MCOs has lost the ability to bind copper.
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