title: Identification and characterization of a novel multicopper oxidase from Acidomyces acidophilus with ferroxidase activity.
abstract: A new multicopper oxidase gene AaMco1 was identified in Acidomyces acidophilus, a pigmented extremophile ascomycete originally isolated from acidic water. Sequence analysis revealed that it encodes a 682 amino acid protein with an apparent molecular mass of 85 kDa as determined by denaturing SDS-PAGE. Interestingly, AaMco1 has a predicted N-terminal transmembrane helix and no signal peptide. To obtain an active and soluble protein, AaMco1 was truncated at its N-terminal to remove the transmembrane helix, but even in this form the protein was found in the insoluble fraction. AaMco1 and its truncated form were then denatured, purified and renatured before characterization. Structural analysis and protein characterization by enzymatic assays indicate that AaMco1 has ferroxidase activity. AaMco1 is also able to oxidize the DMPPDA compound and could be part of a new phylogenetic cluster, the ascomycete MCOs family, described for the first time here.
authors.affiliation: Unité de Recherche en Biologie des Microorganismes, Biology Department, University of Namur, Belgium.
authors.forename: France
authors.initials: F
authors.lastname: Boonen
authors.affiliation: Unité de Recherche en Biologie des Microorganismes, Biology Department, University of Namur, Belgium.
authors.forename: Anne-Michèle
authors.initials: AM
authors.lastname: Vandamme
authors.affiliation: Unité de Recherche en Biologie Environnementale et Evolutive, Biology Department, University of Namur, Belgium.
authors.forename: Emilie
authors.initials: E
authors.lastname: Etoundi
authors.affiliation: Unité de Recherche en Biologie Environnementale et Evolutive, Biology Department, University of Namur, Belgium.
authors.forename: Lise-Marie
authors.initials: LM
authors.lastname: Pigneur
authors.affiliation: Unité de Recherche en Biologie des Microorganismes, Biology Department, University of Namur, Belgium. Electronic address: isabelle.housen@unamur.be.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Housen
mesh_terms: D000595:Amino Acid Sequence; D001203:Ascomycota / Q000201:enzymology*; D002570:Ceruloplasmin / Q000737:chemistry* / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D010088:Oxidoreductases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D010802:Phylogeny; D017433:Protein Structure, Secondary; D017421:Sequence Analysis
chemical_list: D010088:Oxidoreductases; D002570:Ceruloplasmin
keywords: Acidomyces acidophilus; Ferroxidase activity; N-terminal transmembrane helix; New multicopper oxidase