The second cupredoxin domain of the fungal laccases similar to Ma-LCC from Melanocarpus albomyces
The subfamily of fungal laccases includes Ma-LCC and similar proteins. Ma-LCC is a multicopper oxidase (MCO) from Melanocarpus albomyces. Its crystal structure contains all four coppers at the mono- and trinuclear copper centers. Laccase is a blue multi-copper enzyme that catalyzes the oxidation of a variety aromatic - notably phenolic and inorganic substances coupled to the reduction of molecular oxygen to water. It has been implicated in a wide spectrum of biological activities and, in particular, plays a key role in morphogenesis, development and lignin metabolism in fungi and plants. Laccase is 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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