Mitochondrial thioredoxin-2 from disk abalone (Haliotis discus discus): molecular characterization, tissue expression and DNA protection activity of its recombinant protein

Comp Biochem Physiol B Biochem Mol Biol. 2008 Apr;149(4):630-9. doi: 10.1016/j.cbpb.2007.12.009. Epub 2008 Jan 11.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antioxidants / chemistry
  • Antioxidants / isolation & purification
  • Antioxidants / metabolism
  • Cloning, Molecular
  • DNA Damage*
  • DNA, Complementary / genetics
  • DNA, Superhelical / genetics
  • DNA, Superhelical / metabolism
  • Gastropoda / genetics*
  • Gastropoda / metabolism
  • Gene Expression Regulation*
  • Hydrogen Peroxide / pharmacology
  • Mitochondria / genetics*
  • Mitochondria / metabolism
  • Molecular Sequence Data
  • Organ Specificity
  • Oxidative Stress*
  • Phylogeny
  • RNA, Messenger / genetics
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / isolation & purification
  • Recombinant Fusion Proteins / metabolism
  • Sequence Alignment
  • Thioredoxins / chemistry
  • Thioredoxins / genetics*
  • Thioredoxins / isolation & purification
  • Thioredoxins / metabolism*
  • Up-Regulation / drug effects


  • Antioxidants
  • DNA, Complementary
  • DNA, Superhelical
  • RNA, Messenger
  • Recombinant Fusion Proteins
  • Thioredoxins
  • Hydrogen Peroxide

Associated data

  • GENBANK/EF103378