Molecular characterization and expression analysis of iron superoxide dismutase gene from Pseudochlorella pringsheimii (Trebouxiophyceae, Chlorophyta)

Abstract

The FeSOD isoforms of Pseudochlorella pringsheimii were identified, a preliminary characterization of the enzyme was conducted, and the relationship among the FeSOD gene from P. pringsheimii and that of other organisms was examined. The FeSOD has an open reading frame of 612 bp that encodes 203 deduced amino acids with a molecular mass of 23 kDa. Expression of the recombinant FeSOD gene was done successfully in Escherichia coli. The purified FeSOD has a specific enzyme activity that reached 688 U mg-1 protein (in vitro assay). Alkaline conditions showed the highest activity for the recombinant FeSOD. Moreover, it showed a relative thermostability up to 50°C, while at 50 and 70°C, the activity was reduced by 32 and 68%, respectively, after 1 h as compared to the maximum. Phylogenetic analysis revealed three main clusters i.e., the prokaryotic Cyanophyta, bacteria, and the eukaryotic Chlorophyta intermingled with plant species and a dinoflagellate. P. pringsheimii was closely grouped with Chlorella pyrenoidosa, however, other species showed a relative disparity. Alignment of FeSOD gene sequences of the different species showed many conserved regions which could be used for FeSOD sequences among unexplored species and may be useful for the taxonomy of the revised coccoid Chlorella species.

Antioxidant enzymes of Pseudochlorella pringsheimii under two stressors: variation of SOD Isoforms activity

“…pringsheimii was shown to have three SOD isoforms viz. Cu/ZnSOD, MnSOD and FeSOD (Ismaiel and Piercey-Normore 2019 ). In addition, the FeSOD was characterized and expressed in an external bacterial host which yielded constant high levels of activity (Ismaiel and Piercey-Normore 2019 ).…”

“…Cu/ZnSOD, MnSOD and FeSOD (Ismaiel and Piercey-Normore 2019 ). In addition, the FeSOD was characterized and expressed in an external bacterial host which yielded constant high levels of activity (Ismaiel and Piercey-Normore 2019 ). However, the variation of the activity levels of these SOD isoforms may have been due to undetected stress and therefore further investigation is needed to compare different types of stress.…”