title: Identification of a thioredoxin reductase from Babesia microti during mammalian infection.
abstract: Babesia microti is the primary causative agent of human babesiosis worldwide and associated with increased human health risks and the safety of blood supply. The parasite replicates in the host's red blood cells, thus, in order to counteract the oxidative stress and toxic effects, parasites employ a thioredoxin (Trx) system to maintain a redox balance. Since thioredoxin reductase (TrxR) plays a critical role in the system, in this study, we report the cloning, expression, and functional characterization of a novel TrxR from B. microti (BmiTrxR). The complete gene BmiTrxR was obtained by amplifying the 5' and 3' regions of messenger RNA (mRNA) by RACE. The full-length complementary DNA (cDNA) of BmiTrxR was 1766 bp and contained an intact open reading frame with 1662 bp that encoded a polypeptide with 553 amino acids. Molecular weight of the predicted protein was 58.4 kDa with an isoelectric point of 6.95, similar to high molecular weight TrxR. The recombinant protein of BmiTrxR was expressed in a His-fused soluble form in Escherichia coli. The native protein BmiTrxR was identified with the mouse anti-BmiTrxR polyclonal serum by western blotting and IFAT. Moreover, the enzyme showed a disulfide reductase activity using DTNB as substrate and catalyzed the NADPH-dependent reduction of Trx. Auranofin, a known inhibitor of TrxR, completely abrogated the activity of the recombinant enzyme in vitro. These results not only contribute to the understanding of redox pathway in this parasite but also suggest that BmiTrxR could be a potential target for the development of novel strategies to control B. microti thus reducing the incidence of babesiosis.
authors.affiliation: Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China.
authors.forename: Shaoruo
authors.initials: S
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Gong
authors.affiliation: Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China.
authors.forename: Yongzhi
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China.
authors.forename: Houshuang
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Cao
authors.affiliation: Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China. jinlinzhou@shvri.ac.cn.|Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China. jinlinzhou@shvri.ac.cn.
authors.forename: Jinlin
authors.initials: J
authors.lastname: Zhou
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D041001:Babesia microti / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D001404:Babesiosis / Q000469:parasitology*; D001483:Base Sequence; D004795:Enzyme Stability; D006801:Humans; D051379:Mice; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013880:Thioredoxin-Disulfide Reductase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D013879:Thioredoxins / Q000235:genetics
chemical_list: D015800:Protozoan Proteins; D011994:Recombinant Proteins; D013879:Thioredoxins; D009249:NADP; D013880:Thioredoxin-Disulfide Reductase
keywords: Auranofin; Babesia microti; Drug target; Enzyme activity; Thioredoxin reductase