# Expression, Purification, and Anti-UV Irradiation Effect of RsSOD on HCE-T Human Corneal Epithelial Cells

## TL;DR

A radiation-resistant SOD enzyme from a bacterium was purified and shown to protect human corneal cells from UV damage.

## Contribution

The RsSOD protein from Radiobacillus sp. was expressed, purified, and shown to protect HCE-T cells from UV-induced damage.

## Key findings

- RsSOD exhibited high enzyme activity (2072.5 U/mg) and resistance to heat, acid, alkali, and artificial intestinal fluid.
- Low-dose RsSOD (6.25 U/mL) promoted HCE-T cell proliferation and protected against UV-induced damage and apoptosis.
- RsSOD shows potential as a treatment for ocular radiation-related diseases.

## Abstract

Superoxide dismutase (SOD) is a class of enzymes that catalyze the disproportionation of superoxide anion radicals into hydrogen peroxide and oxygen. It can remove excessive free radicals in organisms and acts as a potent antioxidant, cleaning free radicals generated by radiation and protecting cells from oxidative damage. In this study, we obtained a MnSOD gene from the radiation-resistant bacterium Radiobacillus sp. (RsSOD) and constructed its recombinant expression vector through gene synthesis. The recombinant RsSOD protein was efficiently expressed using IPTG induction, and purified via repeated freezing and thawing, heating, and DEAE anion-exchange chromatography. The purified RsSOD exhibited an enzyme activity of 2072.5 U/mg. Furthermore, RsSOD was demonstrated to have robust resistance to high temperatures, acid, alkali, and artificial intestinal fluid. Further studies were performed to investigate the radiation resistance of RsSOD against ultraviolet (UV) irradiation in human corneal epithelial (HCE-T) cells. The results indicated that a low concentration of RsSOD (6.25 U/mL) could promote HCE-T cell proliferation and protect these cells from damage caused by both long-term and short-term UV exposure, effectively reducing apoptosis induced by short-term UV irradiation. These findings suggest that the RsSOD protein possesses significant anti-UV irradiation property and is expected to be a candidate for treating ocular radiation-related diseases.