Masatani Tatsunori, Asada Masahito, Hakimi Hassan, Hayashi Kei, Yamagishi Junya, Kawazu Shin-Ichiro, Xuan Xuenan
Transboundary Animal Diseases Research Center, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima, 890-0065, Japan.
Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan.
Parasitol Res. 2016 Aug;115(8):3139-45. doi: 10.1007/s00436-016-5071-9. Epub 2016 Apr 19.
Cysteine-based peroxidases, known as peroxiredoxins (Prx) or thioredoxin peroxidases (TPx), are important antioxidant enzymes that prevent oxidative damage caused by reactive oxygen species (ROS). In this study, we identified a novel mitochondrial 2-Cys Prx, BbTPx-2, from a bovine Babesia parasite, B. bovis. BbTPx-2 complementary DNA (cDNA) encodes a polypeptide of 254 amino acid residues. This protein has a mitochondrial targeting peptide at the N-terminus and two conserved cysteine residues of the typical 2-Cys Prx. By using a thiol mixed-function oxidation assay, the antioxidant activity of recombinant BbTPx-2 was revealed, and its antioxidant activity was comparable to that of a cytosolic 2-Cys Prx from B. bovis, BbTPx-1. Notably, we confirmed that BbTPx-2 was expressed in the mitochondrion of B. bovis merozoites. Taken together, the results suggest that the mitochondrial BbTPx-2 is an antioxidative enzyme for scavenging ROS in B. bovis.
基于半胱氨酸的过氧化物酶，即过氧化物氧还蛋白（Prx）或硫氧还蛋白过氧化物酶（TPx），是重要的抗氧化酶，可防止活性氧（ROS）造成的氧化损伤。在本研究中，我们从牛巴贝斯虫（B. bovis）中鉴定出一种新型线粒体2-半胱氨酸Prx，即BbTPx-2。BbTPx-2互补DNA（cDNA）编码一个由254个氨基酸残基组成的多肽。该蛋白在N端有一个线粒体靶向肽和典型2-半胱氨酸Prx的两个保守半胱氨酸残基。通过硫醇混合功能氧化试验，揭示了重组BbTPx-2的抗氧化活性，其抗氧化活性与来自牛巴贝斯虫的胞质2-半胱氨酸Prx BbTPx-1相当。值得注意的是，我们证实BbTPx-2在牛巴贝斯虫裂殖子的线粒体中表达。综上所述，结果表明线粒体BbTPx-2是牛巴贝斯虫中清除ROS的抗氧化酶。
