Plasmodium vivax: molecular cloning, expression and characterization of glutathione S-transferase.
Malaria parasite glutathione S-transferases (GSTs) are postulated to be essential for parasite survival by protecting the parasite against oxidative stress and buffering the detoxification of heme-binding compounds; therefore, GSTs are considered potential targets for drug development. In this study, we identified a Plasmodium vivax gene encoding GST (PvGST) and characterized the biochemical properties of the recombinant enzyme. The PvGST contained 618 bp that encoded 205 amino acids and shared a significant degree of sequence identity with GSTs from other Plasmodium species. The recombinant homodimeric enzyme had an approximate molecular mass of 50kDa and exhibited GSH-conjugating and GSH-peroxidase activities towards various model substrates. The optimal pH for recombinant PvGST (rPvGST) activity was pH 8.0, and the enzyme was moderately unstable at 37 degrees C. The K(m) values of rPvGST with respect to GSH and CDNB were 0.17+/-0.09 and 2.1+/-0.4mM, respectively. The significant sequence homology and similar biochemical properties of PvGST and Plasmodium falciparum GST (PfGST) indicate that they may have similar molecular structures. This information may be useful for the design of specific inhibitors for plasmodial GSTs as potential antimalarial drugs.
Na
Byoung-Kuk
BK
Department of Parasitology and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 660-751, Republic of Korea.
Kang
Jung-Mi
JM
Kim
Tong-Soo
TS
Sohn
Woon-Mok
WM
D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D015971:Gene Expression Regulation, Enzymologic; D005982:Glutathione Transferase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D016780:Malaria, Vivax / Q000469:parasitology*; D008969:Molecular Sequence Data; D010966:Plasmodium vivax / Q000201:enzymology* / Q000235:genetics*; D016415:Sequence Alignment; D013379:Substrate Specificity
D005982:Glutathione Transferase