title: Cloning and characterization of the genes encoding the high-affinity iron-uptake protein complex Fet3/Ftr1 in the basidiomycete Phanerochaete chrysosporium.
abstract: MCO1, a multicopper oxidase from Phanerochaete chrysosporium exhibiting strong ferroxidase activity, has recently been described. This enzyme shows biochemical and structural similarities with the yeast Fet3p, a type I membrane glycoprotein that efficiently oxidizes Fe(II) to Fe(III) for its subsequent transport to the intracellular compartment by the iron permease Ftr1p. The genome database of P. chrysosporium was searched to verify whether it includes a canonical fet3 in addition to mco1, and single copies of fet3 and ftr1 orthologues were found, separated by a divergent promoter. Pc-fet3 encodes a 628 aa protein that exhibits overall identities of about 40 % with other reported Fet3 proteins. In addition to a secretion signal, it has a C-terminal transmembrane domain, characteristic of these cell-surface-attached ferroxidases. Structural modelling of Pc-Fet3 revealed that the active site has all the residues known to be essential for ferroxidase activity. Pc-ftr1 encodes a 393 aa protein that shows about 38 % identity with several Ftr1 proteins from ascomycetes. Northern hybridization studies showed that the mRNA levels of both genes are reduced upon supplementation of the growth medium with iron, supporting the functional coupling of Fet3 and Ftr1 proteins in vivo.
authors.affiliation: Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile and Instituto Milenio de Biología Fundamental y Aplicada, Santiago, Chile.
authors.forename: Luis F
authors.initials: LF
authors.lastname: Larrondo
authors.affiliation: Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile and Instituto Milenio de Biología Fundamental y Aplicada, Santiago, Chile.
authors.forename: Paulo
authors.initials: P
authors.lastname: Canessa
authors.affiliation: Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile and Instituto Milenio de Biología Fundamental y Aplicada, Santiago, Chile.
authors.forename: Francisco
authors.initials: F
authors.lastname: Melo
authors.affiliation: Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile and Instituto Milenio de Biología Fundamental y Aplicada, Santiago, Chile.
authors.forename: Rubén
authors.initials: R
authors.lastname: Polanco
authors.affiliation: Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile and Instituto Milenio de Biología Fundamental y Aplicada, Santiago, Chile.
authors.forename: Rafael
authors.initials: R
authors.lastname: Vicuña
mesh_terms: D001665:Binding Sites; D015152:Blotting, Northern; D002570:Ceruloplasmin / Q000235:genetics; D003001:Cloning, Molecular; D004271:DNA, Fungal; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D007501:Iron / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000235:genetics*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020075:Phanerochaete / Q000235:genetics* / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D021382:Protein Sorting Signals / Q000235:genetics; D017434:Protein Structure, Tertiary; D012329:RNA, Bacterial / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D021382:Protein Sorting Signals; D012329:RNA, Bacterial; D012333:RNA, Messenger; D007501:Iron; D002570:Ceruloplasmin