Fasciola hepatica: Heterologous expression and functional characterizationof a thioredoxin peroxidase

A Fasciola hepatica cDNA clone of 779 bp was isolated from an adult worm cD NA expression library by immunological screening using a rabbit serum again st the excretory-secretory antigens. The nucleotide sequence of the cDNA re vealed the presence of an open reading frame of 582 bp which encoded a 194- amino-acid-residue polypeptide (M-r 21,723 Da) showing a high degree of hom ology to thioredoxin peroxidases. This putative antioxidant protein gene wa s expressed in Escherichia coli as a GST fusion protein. The recombinant fu sion protein showed in vitro antioxidant properties and protected rabbit mu scle enolase and E. coli glutamine synthetase from inactivation by nonenzym atic Fe3+/O-2/DTT or Fe3+/O-2/ascorbate metal-catalyzed oxidation systems. (C) 2000 Academic Press.