title: A thioredoxin from antarctic microcrustacean (Euphausia superba): Cloning and functional characterization.
abstract: Thioredoxins, with a dithiol/disulfide active site (CGPC) are major highly conserved and ubiquitous proteins that are involved in protecting organisms against various oxidative stresses. In the present study, a novel thioredoxin gene was identified in antarctic microcrustacean, Euphausia superba (designated as EsTrx1). The full-length cDNA sequences of EsTrx1 was of 621 bp, containing a 5' untranslated region (UTR) of 45 bp, a 3' UTR of 276 bp and an open reading frame (ORF) of 303 bp encoding a putative protein of 100 amino acids. The predicted molecular weight of EsTrx1 was 11.08 kDa and the theoretical isoelectric point was 4.51. Multiple sequence alignment indicated that the EsTrx1 possessed conserved CGPC redox-active site. EsTrx1 shared 68.6% similarity with the Chinese mitten crab (Eriocheir sinensis) Trx1. The predicted three-dimensional structure of EsTrx1 consisted of a central core of a four-stranded β-sheet and four flanking α-helices. The high similarity of EsTrx1 with Trx1s from other animals together with the phylogenetic analysis indicated that EsTrx1 could be a novel member of Trx1 sub-family. In order to elucidate its biological functions, the recombinant EsTrx1 was constructed and expressed in Escherichia coli BL21 (DE3). Experiments demonstrated that the rEsTrx1 fusion protein possessed the expected redox activity in enzymatic analysis, and be more potent than GSH in antioxidant capacity. These results together indicated that EsTrx1 could be involved in the oxidative stress response of E. superba.
authors.affiliation: Qingdao University of Science and Technology, Qingdao 266042, China. Electronic address: lifengmei@qust.edu.cn.
authors.forename: Fengmei
authors.initials: F
authors.lastname: Li
authors.affiliation: East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai 200090, China.
authors.forename: Liyan
authors.initials: L
authors.lastname: Ma
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
authors.forename: Huan
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Qingdao University of Science and Technology, Qingdao 266042, China.
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.affiliation: Qingdao University of Science and Technology, Qingdao 266042, China.
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Zhu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D060829:Arthropod Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D033201:Euphausiacea / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D012313:RNA / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013879:Thioredoxins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D060829:Arthropod Proteins; D018076:DNA, Complementary; D011994:Recombinant Proteins; D013879:Thioredoxins; D012313:RNA
keywords: Antioxidant enzyme; Euphausia superba; Microcrustacean; Oxidative stress; Thioredoxin