title: Cloning and functional characterisation of a peroxiredoxin 1 (NKEF A) cDNA from Atlantic salmon (Salmo salar) and its expression in fish infected with Neoparamoeba perurans.
abstract: Peroxiredoxin 1 (Prx 1), also known as natural killer enhancing factor A (NKEF A), has been implicated in the immune response of both mammals and fish. Amoebic gill disease (AGD), caused by Neoparamoeba perurans, is a significant problem for the Atlantic salmon (Salmo salar L.) aquaculture industry based in Tasmania, Australia. Here we have cloned and functionally characterized a Prx 1 open reading frame (ORF) from Atlantic salmon liver and shown that Prx 1 gene expression was down-regulated in the gills of Atlantic salmon displaying symptoms of AGD. The Prx 1 ORF encoded all of the residues and motifs characteristic of typical 2-Cys Prx proteins from eukaryotes and the recombinant protein expressed in Escherichia coli catalyzed thioredoxin (Trx)-dependent reduction of H(2)O(2), cumene hydroperoxide (CuOOH) and t-butyl hydroperoxide (t-bOOH) with K(m) values of 122, 77 and 91 μM, respectively, confirming that it was a genuine 2-Cys Prx. The recombinant protein also displayed a double displacement reaction mechanism and a catalytic efficiency (k(cat)/K(m)) with H(2)O(2) of 1.5 × 10(5) M(-1) s(-1) which was consistent with previous reports for the 2-Cys Prx family of proteins. This is the first time that a Prx 1 protein has been functionally characterized from any fish species and it paves the way for further investigation of this important 2-Cys Prx family member in fish.
authors.affiliation: School of Biological Sciences, Flinders University, Adelaide, SA 5001, Australia.
authors.forename: Grace H
authors.initials: GH
authors.lastname: Loo
authors.forename: Drew L
authors.initials: DL
authors.lastname: Sutton
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Schuller
mesh_terms: D000562:Amebiasis / Q000276:immunology / Q000662:veterinary*; D000595:Amino Acid Sequence; D056894:Amoebozoa / Q000276:immunology; D000818:Animals; D018076:DNA, Complementary / Q000235:genetics; D005393:Fish Diseases / Q000276:immunology*; D005786:Gene Expression Regulation; D005880:Gills / Q000276:immunology / Q000469:parasitology; D008969:Molecular Sequence Data; D054464:Peroxiredoxins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology*; D010802:Phylogeny; D011994:Recombinant Proteins / Q000378:metabolism; D020317:Salmo salar / Q000145:classification / Q000276:immunology*; D016415:Sequence Alignment
chemical_list: D018076:DNA, Complementary; D011994:Recombinant Proteins; D054464:Peroxiredoxins