Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10821736 | Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology | 2012 | 12 Pages |
Abstract
Glutathione S-transferases (GSTs) are versatile enzymes, act as primary intracellular detoxifiers and contribute to a broad range of physiological processes including cellular defense. In this study, a full-length cDNA representing a novel sigma-like GST was identified from Manila clam, Ruditapes philippinarum (RpGSTÏ). RpGSTÏ (884 bp) was found to possess an open reading frame of 609 bp. The encoded polypeptide (203 amino acids) had a predicted molecular mass of 23.21 kDa and an isoelectric point of 7.64. Sequence analysis revealed two conserved GST domain profiles in N- and C-termini. Alignment studies revealed that the identity between deduced peptides of RpGSTÏ and known GSTÏ members was relatively low (< 35%), except a previously identified Manila clam GSTÏ isoform (87.2%). Phylogenetic analysis indicated that RpGSTÏ clustered together with molluscan GSTÏ homologs, which were closely related to insect GSTÏs. The RpGSTÏ was subsequently cloned and expressed as recombinant protein, in order to characterize its biological activity. The recombinant RpGSTÏ exhibited characteristic glutathione conjugating catalytic activity toward 1-chloro-2,4-dinitrobenzene, 3,4-dichloronitrobenzene and ethacrynic acid. It had an optimal pH and temperature of 8.0 and 35 °C, respectively. Expression profiles under normal conditions and in response to lipopolysaccharide-, poly I:C- and Vibrio tapetis-challenges were also investigated. RpGSTÏ demonstrated a differential tissue distribution with robust transcription in gills of normal animals. We explored potential association of GSTÏ in cellular defense during bacterial infection and found that in challenged clams, RpGSTÏ gene was significantly induced in internal and external tissues, in conjunction with manganese- as well as copper-zinc superoxide dismutase (MnSOD and CuZnSOD) genes. Moreover, the induction was remarkably higher in hemocytes than in gill. Collectively, our findings suggested that RpGSTÏ could play a significant role in cellular defense against oxidative stress caused by bacteria, in conjunction with other antioxidant enzymes, such as SODs.
Keywords
Related Topics
Life Sciences
Biochemistry, Genetics and Molecular Biology
Biochemistry
Authors
Navaneethaiyer Umasuthan, Kasthuri Saranya Revathy, Youngdeuk Lee, Ilson Whang, Cheol Young Choi, Jehee Lee,