School of Marine and Technology, Harbin Institute of Technology, Weihai, 264209, People's Republic of China.
Mol Biol Rep. 2013 Dec;40(12):6587-91. doi: 10.1007/s11033-013-2771-4. Epub 2013 Sep 26.
Thioredoxin (Trx) is a highly conserved and multi-functional protein that plays a pivotal role in maintaining the redox state of the cell and in protecting the cell against oxidative stress. Trx gene from Antarctic sea-ice bacteria Pseudoalteromonas sp. AN178 was cloned and expressed as soluble protein in Escherichia coli (designated as PsTrx). Trx gene consisted of an open reading frame of 324-bp nucleotides encoding a protein of 108 amino acids with a calculated molecular mass of 11.88 kDa. The deduced protein included the conserved Cys-Gly-Pro-Cys active-site sequence. After purification by a single step Ni-NTA affinity chromatography, recombinant PsTrx with a high specific activity of 96.67 U/mg was obtained. The purified PsTrx had an optimal temperature and pH of 25 °C and 7.0, respectively, and showed about 55 % of the residual catalytic activity even at 0-10 °C. It had high tolerance to a wide range of NaCl concentrations (0-2 M NaCl) and was stable in the presence of H2O2. This research suggested that PsTrx displayed unique catalytic properties.
硫氧还蛋白（Trx）是一种高度保守且多功能的蛋白质，在维持细胞的氧化还原状态和保护细胞免受氧化应激方面起着关键作用。来自南极海冰细菌假交替单胞菌 AN178 的 Trx 基因被克隆并在大肠杆菌中表达为可溶性蛋白（命名为 PsTrx）。Trx 基因由一个 324 个核苷酸的开放阅读框编码，该基因编码一个由 108 个氨基酸组成的蛋白质，分子量为 11.88 kDa。推导的蛋白质包括保守的 Cys-Gly-Pro-Cys 活性位点序列。通过一步 Ni-NTA 亲和层析纯化后，获得了具有 96.67 U/mg 高比活性的重组 PsTrx。纯化的 PsTrx 的最适温度和 pH 值分别为 25°C 和 7.0，即使在 0-10°C 下，其残余催化活性仍约为 55%。它对广泛的 NaCl 浓度（0-2 M NaCl）具有高耐受性，并且在存在 H2O2 的情况下稳定。这项研究表明 PsTrx 表现出独特的催化特性。
