School of Marine Science and Technology, Harbin Institute of Technology, Weihai 264209, China.
Mar Drugs. 2019 Mar 1;17(3):147. doi: 10.3390/md17030147.
Glutathione S-transferases are one of the most important antioxidant enzymes to protect against oxidative damage induced by reactive oxygen species. In this study, a novel gene, designated as , was derived from Antarctic sea ice bacterium sp. ANT108 and expressed in () BL21. The gene was 603 bp in length and encoded a protein of 200 amino acids. Compared with the mesophilic EcGST, homology modeling indicated HsGST had some structural characteristics of cold-adapted enzymes, such as higher frequency of glycine residues, lower frequency of proline and arginine residues, and reduced electrostatic interactions, which might be in relation to the high catalytic efficiency at low temperature. The recombinant HsGST (rHsGST) was purified to apparent homogeneity with Ni-affinity chromatography and its biochemical properties were investigated. The specific activity of the purified rHsGST was 254.20 nmol/min/mg. The optimum temperature and pH of enzyme were 25 °C and 7.5, respectively. Most importantly, rHsGST retained 41.67% of its maximal activity at 0 °C. 2.0 M NaCl and 0.2% H₂O₂ had no effect on the enzyme activity. Moreover, rHsGST exhibited its protective effects against oxidative stresses in cells. Due to its high catalytic efficiency and oxidative resistance at low temperature, rHsGST may be a potential candidate as antioxidant in low temperature health foods.
谷胱甘肽 S-转移酶是保护机体免受活性氧诱导的氧化损伤的最重要的抗氧化酶之一。本研究从南极海冰细菌 sp.ANT108 中克隆了一个新基因，命名为 ，并在大肠杆菌 BL21 中表达。该基因全长 603bp，编码 200 个氨基酸的蛋白质。与嗜温菌 EcGST 相比，同源建模表明 HsGST 具有一些适应低温的酶的结构特征，如甘氨酸残基的频率更高、脯氨酸和精氨酸残基的频率更低以及静电相互作用减少，这可能与低温下高催化效率有关。用 Ni 亲和层析法纯化重组 HsGST(rHsGST)至明显均一，并研究了其生化性质。纯化的 rHsGST 的比活性为 254.20nmol/min/mg。酶的最适温度和 pH 值分别为 25°C 和 7.5。最重要的是，rHsGST 在 0°C 时保留了其最大活性的 41.67%。2.0M NaCl 和 0.2%H₂O₂对酶活性没有影响。此外，rHsGST 在 细胞中表现出对氧化应激的保护作用。由于其在低温下具有高催化效率和抗氧化性，rHsGST 可能是低温保健食品中抗氧化剂的潜在候选物。
