Cloning, expression, and characterization of a novel superoxide dismutase from deep-sea sea cucumber

Superoxide dismutases (SODs) are the first line of defense against oxidative damage caused by reactive oxygen species and are associated with stress tolerance. Accordingly, many studies have focused on SODs, especially those from extreme habitats. In this study, we reported a novel Cu,Zn-SOD from the new species Benthodytes marianensis sp. nov (hereafter denoted as Bm-Cu,Zn-SOD) collected from the Mariana Trench. The purified recombinant enzyme with an approx. Mr. of 38 kDa was intracellular and dimeric, and it expressed activity at an optimal temperature of 30 °C and optimum pH of 7.4. The Km and Vmax values of Bm-Cu,Zn-SOD were 0.046 ± 0.004 mM and 1209.151 ± 24.057 U/mg, respectively. Under the tested conditions, Bm-Cu,Zn-SOD resisted interference from chemicals (β-mercaptoethanol and ethylenediaminetetraacetic acid), denaturants (urea and guanidine hydrochloride), and high salinity, showing high kinetic stability. Furthermore, Bm-Cu,Zn-SOD could be activated by high hydrostatic pressure. All these properties suggested adaptation to the deep-sea environment and thus indicated its potential future applications.