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

作者：De Zoysa Mahanama; Pushpamali Wickramaarachchilage Anoja; Whang Son; Kim Se Jae; Lee Jehee^*

来源：Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology, 2008, 149(4): 630-639.

DOI：10.1016/j.cbpb.2007.12.009

• abalone
• antioxidant
• mitochondria
• oxidative stress
• ROS
• thioredoxin-2

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 H2O2 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.

• 出版日期2008-4