title: Mitochondrial thioredoxin-2 from disk abalone (Haliotis discus discus): molecular characterization, tissue expression and DNA protection activity of its recombinant protein.
abstract: Thioredoxin-2 is a mitochondria-specific member of the thioredoxin (TRx) super-family that plays an important role as a component of the mitochondrial antioxidant system. The gene coding mitochondrial TRx-2 was isolated from the disk abalone (Haliotis discus discus) cDNA library, denoted as AbTRx-2. It contains 1214-bp full length with 519-bp open reading frame, encoding 173 amino acids. AbTRx-2 showed characteristic TRx active site at (96)WCGPC(100) and mitochondrial targeting peptide at the N-terminal amino acid sequence. The deduced amino acid comparison showed that AbTRx-2 shares 43 and 42% identity with Xenopus laevis and human TRx-2, respectively. Purified recombinant AbTRx-2 fusion protein was shown to catalyze insulin reduction and protect supercoiled plasmid DNA from damages induced by metal-catalyzed generation of reactive oxygen species. Constitutive AbTRx-2 mRNA was detected in gill, mantle, gonad, abductor muscle, digestive tract, and hemocytes, in a tissue specific manner. The AbTRx-2 mRNA was up-regulated in gill and digestive tract tissues initially at 3 h post-injection of H(2)O(2) and maintained higher level at 6 h. Our results suggest that abalone TRx-2 may play an important role in regulating oxidative stress in mitochondria by catalyzing protein disulfide reduction, scavenging of ROS, and minimizing the DNA damage.
authors.affiliation: Department of Marine Biotechnology, College of Ocean Science, Cheju National University, Ara-Dong, 690-756, Republic of Korea.
authors.forename: Mahanama
authors.initials: M
authors.lastname: De Zoysa
authors.forename: Wickramaarachchilage Anoja
authors.initials: WA
authors.lastname: Pushpamali
authors.forename: Ilson
authors.initials: I
authors.lastname: Whang
authors.forename: Se Jae
authors.initials: SJ
authors.lastname: Kim
authors.forename: Jehee
authors.initials: J
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D003001:Cloning, Molecular; D004249:DNA Damage; D018076:DNA, Complementary / Q000235:genetics; D004278:DNA, Superhelical / Q000235:genetics / Q000378:metabolism; D049851:Gastropoda / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008928:Mitochondria / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009928:Organ Specificity; D018384:Oxidative Stress; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment; D013879:Thioredoxins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000975:Antioxidants; D018076:DNA, Complementary; D004278:DNA, Superhelical; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D013879:Thioredoxins; D006861:Hydrogen Peroxide