In molecular biology, multicopper oxidases are enzymes which oxidise their substrate by accepting electrons at a mononuclear copper centre and transferring them to a trinuclear copper centre; dioxygenbinds to the trinuclear centre and, following the transfer of four electrons, is reduced to two molecules of water.[1] There are three spectroscopically different copper centres found in multicopper oxidases: type 1 (or blue), type 2 (or normal) and type 3 (or coupled binuclear).[2][3] Multicopper oxidases consist of 2, 3 or 6 of these homologous domains, which also share homology with the cupredoxins azurin and plastocyanin. Structurally, these domains consist of a cupredoxin-like fold, a beta-sandwich consisting of 7 strands in 2 beta-sheets, arranged in a Greek-key beta-barrel.[4]
Multicopper oxidase (type 1)
crystal structures of e. coli laccase cueo under different copper binding situations
The family of multicopper oxidases can be divided into three groups based on the electron-donating substrate. [5] Laccases oxidize a variety of organic substrates, metalloxidases accept metal substrates and a third group contains multicopper oxidases that are specific towards one single substrate. Multicopper oxidases include:
^Ouzounis C, Sander C (February 1991). "A structure-derived sequence pattern for the detection of type I copper binding domains in distantly related proteins". FEBS Lett. 279 (1): 73–8. doi:10.1016/0014-5793(91)80254-Z. PMID1995346. S2CID10299194.
^Suzuki S, Kataoka K, Yamaguchi K (October 2000). "Metal coordination and mechanism of multicopper nitrite reductase". Acc. Chem. Res. 33 (10): 728–35. doi:10.1021/ar9900257. PMID11041837.
^Mann KG, Jenny RJ, Krishnaswamy S (1988). "Cofactor proteins in the assembly and expression of blood clotting enzyme complexes". Annu. Rev. Biochem. 57: 915–56. doi:10.1146/annurev.bi.57.070188.004411. PMID3052293.
^Askwith C, Eide D, Van Ho A, Bernard PS, Li L, Davis-Kaplan S, Sipe DM, Kaplan J (January 1994). "The FET3 gene of S. cerevisiae encodes a multicopper oxidase required for ferrous iron uptake". Cell. 76 (2): 403–10. doi:10.1016/0092-8674(94)90346-8. PMID8293473. S2CID27473253.