Molecular cloning and functional characterization of MnSOD from Dunaliella salina

Abstract

Dunaliella salina, a unicellular green alga, has the potential to grow in hypersaline environments via one of its gene products, superoxide dismutase (SOD). The superoxide radicals (O2 (-) ) produced by environmental stresses can cause damage to cells, and SOD catalyzes the turnover of such free radicals to protect cells. In this study, the gene coding for SOD in D. salina was cloned and the product was further identified and characterized. The open reading frame of this gene was 651 bp long, encoding for 217 amino acids. According to the sequence alignment using BLAST, native polyacrylamide electrophoresis for SOD activity analysis, and atomic absorption spectroscopy analysis, this protein belongs to the manganese-containing superoxide dismutase (MnSOD) family. Complementation analysis, performed by introducing plasmids carrying an inducible version of the D. salina gene encoding for MnSOD into an SOD-deficient mutant of E.coli, revealed that this gene could not only complement the defects in SOD activity, but was also capable of providing a stronger tolerance to restrictive growth conditions, such as high salt and prolonged UV exposure, compared to the tolerance of wild-type strains.

Molecular characterization and expression analysis of copper‐zinc superoxide dismutases from the freshwater alga Closterium ehrenbergii under metal stress

“…Of these, CuZnSOD has different primary and tertiary structures compared to Fe/MnSOD and has almost certainly evolved independently . Previous studies have reported that both transcription and enzymatic activity of SODs are sensitive to environmental stresses such as exposure to heavy metals, biocides, and/or heat shock . For these reasons, SOD has been frequently used as an ecotoxicological biomarker in many aquatic organisms …”

Biochemical and Molecular Characterization of a Novel Cu/Zn Superoxide Dismutase from Amaranthus hypochondriacus L.: an Intrinsically Disordered Protein

“…S6). Similarly, it has been reported that E. coli expressing the MnSOD from Dunaliella salina displays resistance to concentrations higher than 10 % (1.7 M NaCl) [42]. Remarkable E. coli expressing the recombinant CtSOD from C. thermophilum displays high salt tolerance (up to 3 M NaCl), indicating that it is an excellent stress protectant protein [36].…”

Identification of Targets of Transcription Factor WRINKLED1-Like Related to Lipid Biosynthesis From Marine Microalga Dunaliella parva

“…Dunaliella parva is a unicellular halophilic green alga, which simultaneously accumulates lipids and large amounts of carotenoids (primarily beta-carotene), and shows a good resistance against unfavorable ambient conditions such as UV-A radiation, salinity up-shock, extreme pH and temperature, and nitrogen limitation (Mogedas et al, 2009;Borowitzka, 2013;Zhang et al, 2014;Srinivasan et al, 2015). In addition, D. parva has no rigid cell wall, which is favorable for genetic manipulation and extraction (Hosseini-Tafreshi and Shariati, 2009;Barzegari et al, 2010).…”