title: Characterization of glutathione S-transferases from Sus scrofa, Cydia pomonella and Triticum aestivum: their responses to cantharidin.
abstract: Glutathione S-transferases (GSTs) play a key role in detoxification of xenobiotics in organisms. However, their other functions, especially response to the natural toxin cantharidin produced by beetles in the Meloidae and Oedemeridae families, are less known. We obtained GST cDNAs from three sources: Cydia pomonella (CpGSTd1), Sus scrofa (SsGSTα1), and Triticum aestivum (TaGSTf3). The predicted molecular mass is 24.19, 25.28 and 24.49 kDa, respectively. These proteins contain typical N-terminal and C-terminal domains. Recombinant GSTs were heterologously expressed in Escherichia coli as soluble fusion proteins. Their optimal activities are exhibited at pH 7.0-7.5 at 30 °C. Activity of CpGSTd1 is strongly inhibited by cantharidin and cantharidic acid, but is only slightly suppressed by the demethylated analog of cantharidin and cantharidic acid. Enzymatic assays revealed that cantharidin has no effect on SsGSTα1 activity, while it significantly stimulates TaGSTf3 activity, with an EC50 value of 0.3852 mM. Activities of these proteins are potently inhibited by the known GST competitive inhibitor: S-hexylglutathione (GTX). Our results suggest that these GSTs from different sources share similar structural and biochemical characteristics. Our results also suggest that CpGSTd1 might act as a binding protein with cantharidin and its analogs.
authors: Key Laboratory of Plant Protection Resources & Pest Management of the Ministry of Education, College of Plant Protection, Northwest A & F University, Yangling, Shaanxi 712100, China; College of Plant Protection, Shenyang Agricultural University, Shenyang 110866, Liaoning, China.
authors: Xue-Qing
authors: XQ
authors: Yang
authors: Key Laboratory of Plant Protection Resources & Pest Management of the Ministry of Education, College of Plant Protection, Northwest A & F University, Yangling, Shaanxi 712100, China. Electronic address: yalinzh@nwsuaf.edu.cn.
authors: Ya-Lin
authors: YL
authors: Zhang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002193:Cantharidin / Q000031:analogs & derivatives / Q000633:toxicity*; D004791:Enzyme Inhibitors / Q000633:toxicity; D005978:Glutathione / Q000031:analogs & derivatives / Q000494:pharmacology; D005982:Glutathione Transferase / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D008658:Inactivation, Metabolic; D019476:Insect Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009036:Moths / Q000201:enzymology* / Q000235:genetics; D010802:Phylogeny; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D034421:Sus scrofa; D014908:Triticum / Q000201:enzymology* / Q000235:genetics; D015262:Xenobiotics / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D019476:Insect Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D015262:Xenobiotics; D005982:Glutathione Transferase; D005978:Glutathione; D002193:Cantharidin; C033550:hexylglutathione
keywords: Binding protein; Biochemical characterization; Cantharidin; Glutathione S-transferases; Stress