Cold-Adapted Glutathione S-Transferases from Antarctic Psychrophilic Bacterium Halomonas sp. ANT108: Heterologous Expression, Characterization, and Oxidative Resistance

Abstract

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 gst gene, designated as hsgst, was derived from Antarctic sea ice bacterium Halomonas sp. ANT108 and expressed in Escherichia coli (E. coli) BL21. The hsgst 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 E. coli 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.

A New Cold-Adapted and Salt-Tolerant Glutathione Reductase from Antarctic Psychrophilic Bacterium Psychrobacter sp. and Its Resistance to Oxidation

“…The ΔG values of the NADPH substrate increased from 60.07 to 61.80 kJ/mol as the temperature increased from 0 to 25 °C, suggesting that the thermostability of the rPsGR increased as the temperature increased. This trend was also observed in other coldadapted enzymes [16,38]. Additionally, the enthalpy of activation, ΔH, showed a downward trend from 0 to 25 °C.…”

“…In recent years, the Antarctic has attracted attention due to its special climate [14,15]. The unique biochemical functions of cold-adapted enzymes play an important role in the adaptation of sea-ice bacteria [16,17]. Based on the importance of GRs in the cellular physiology and biochemistry related to cold adaptation, and to discover and understand their biochemical properties, cold-adaptation and structure deserve further investigation.…”

Salt stress improves thermotolerance and high-temperature bioethanol production of multi-stress-tolerant Pichia kudriavzevii by stimulating intracellular metabolism and inhibiting oxidative damage

“…Moreover, salt stress significantly improved its precursor compounds, among which γ-glutamylcysteine increased by 2.1 and 1.2 times, while S-lactoylglutathione increased by 19.6 and 83.6 times after addition of 100 and 300 mmol/L NaCl, respectively. Glutathione S-transferases (GSTs) can catalyze the reaction of GSH with oxidative damage by-products of biomolecules to minimize the oxidative damage and prooxidant-induced cell death [ 34 , 35 ]. In this study, the gene coding for glutathione S-transferase Y-2 (BOH78_1912) was significantly up-regulated by salt stress, especially at 300 mmol/L NaCl with the improved expression by 76.1 times.…”

Cold Adaptation Strategies and the Potential of Psychrophilic Enzymes from the Antarctic Yeast, Glaciozyma antarctica PI12

“…Similar results were observed in another psychrophilic yeast, M. psychrophilia , where the superoxide dismutase genes were not upregulated [ 23 ]. To overcome environmental stress, G. antarctica expresses genes encoding for glutathione S-transferase ( GST ), which are important to cleanse ROS formed during metabolism [ 58 , 59 ]. GST also plays an important part in cell protection from oxidative burst by catalyzing various substrates and quenching reactive molecules.…”