Characterization of an omega-class glutathione S-transferase from Schistosoma mansoni with glutaredoxin-like dehydroascorbate reductase and thiol transferase activities.
Glutathione S-transferases (EC 2.5.1.18) (GSTs), are a family of multifunctional enzymes present in all living organisms whose main function is the detoxification of electrophilic compounds. GSTs are considered the most prominent detoxifying class II enzymes in helminths. We describe here the characterization of novel dehydroascorbate reductase and thiol transferase activities that reside in the human parasite Schistosoma mansoni GSTx. Protein sequence analysis of this parasite product showed lower identity to known GSTs. However, phylogenic analysis placed SmGSTx among the recently described omega class GSTs (GSTO1-1). We report here that SmGSTO protein is a 28-kDa polypeptide, detected in all life stages of the parasite, being highly expressed in adult worms. Like other omega class GSTs, SmGSTO showed very low activity toward classical GSTs substrates as 1-chloro-2,4-dinitrobenzene, and no binding affinity to glutathione-agarose matrix but showed some biochemical characteristics related with thioredoxins/glutaredoxins. Interestingly, SmGSTO was able to bind S-hexyl glutathione matrix and displayed significant glutathione-dependent dehydroascorbate reductase and thiol transferase enzymatic activities.
Girardini
Javier
J
Instituto de Biología Molecular y Celular de Rosario, IBR-CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, UNR; and Facultad de Odontología, UNR, Rorario, Argentina.
Amirante
Alejandro
A
Zemzoumi
Khalid
K
Serra
Esteban
E
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003062:Codon; D018076:DNA, Complementary / Q000378:metabolism; D020224:Expressed Sequence Tags; D054477:Glutaredoxins; D005982:Glutathione Transferase / Q000737:chemistry* / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000737:chemistry*; D010802:Phylogeny; D011485:Protein Binding; D011490:Protein Disulfide Reductase (Glutathione); D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012550:Schistosoma mansoni / Q000201:enzymology*; D013379:Substrate Specificity
D003062:Codon; D018076:DNA, Complementary; D054477:Glutaredoxins; D011994:Recombinant Proteins; D010088:Oxidoreductases; D011490:Protein Disulfide Reductase (Glutathione); C020666:glutathione dehydrogenase (ascorbate); D005982:Glutathione Transferase