Tanaka Miho, Sakurai Tatsuya, Yokoyama Naoaki, Inoue Noboru, Kawazu Shin-ichiro
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
Parasitol Res. 2009 Oct;105(5):1473-7. doi: 10.1007/s00436-009-1587-6. Epub 2009 Aug 13.
We have identified the 2-Cys peroxiredoxin (Prx) from a bovine Babesia parasite, B. bovis. Prx is a recently described family of antioxidant enzymes that are highly conserved in eukaryotes and prokaryotes. B. bovis 2-Cys Prx (BbTPx-1) contained two conserved cysteine residues that corresponded to Cys47 and Cys170 of the yeast Prx and the amino acid sequences of two catalytic domains showed significant similarities to those of mammalian typical 2-Cys Prx. The antioxidant activity of the recombinant BbTPx-1 protein expressed in E. coli was demonstrated by a thiol mixed-function oxidation assay. Furthermore, we confirmed that BbTPx-1 was expressed in the cytoplasm of intra-erythrocytic B. bovis merozites. These results suggest that B. bovis likely uses TPx-1 as a way to reduce peroxides as a control of its intracellular redox balance so that it can live and grow in the host cell.
我们已从牛巴贝斯虫（B. bovis）中鉴定出2-半胱氨酸过氧化物酶（Prx）。Prx是最近描述的一类抗氧化酶家族，在真核生物和原核生物中高度保守。牛巴贝斯虫2-半胱氨酸Prx（BbTPx-1）含有两个保守的半胱氨酸残基，分别对应于酵母Prx的Cys47和Cys170，且两个催化结构域的氨基酸序列与哺乳动物典型的2-半胱氨酸Prx的序列具有显著相似性。通过硫醇混合功能氧化试验证明了在大肠杆菌中表达的重组BbTPx-1蛋白的抗氧化活性。此外，我们证实BbTPx-1在红细胞内牛巴贝斯虫裂殖子的细胞质中表达。这些结果表明，牛巴贝斯虫可能利用TPx-1作为减少过氧化物的一种方式，以控制其细胞内的氧化还原平衡，从而使其能够在宿主细胞中生存和生长。
