Radioprotective Protein of Tardigrades Dsup (Damage Suppressor) is Resistant to High Doses of Ionizing Radiation

Abstract

The unique protein Dsup of the tardigrade Ramazzottius varieornatus increases resistance to radiation and oxidative stress in various organisms and in human cell culture. According to simulation data, Dsup forms a complex with DNA with an intermolecular distance of \({\sim}4\) Å, as a result of which DNA is less damaged by reactive oxygen species generated during radiation exposure. However, the stability of the Dsup protein itself under the effect of ionizing radiation remains unclear, which is important for assessing its radioprotective potential and understanding the molecular mechanisms of action of this protein under conditions of high doses of radiation. In this work, the radiation degradation of the Dsup protein after irradiation with \(\gamma\)-quanta using small-angle X-ray scattering (SAXS) and electrophoresis of proteins in polyacrylamide gel under denaturing conditions (SDS-PAGE) was studied for the first time. It was shown that, unlike the control protein bovine serum albumin, the spatial-structural characteristics of the Dsup protein remain almost unchanged even when exposed high doses of radiation (5 and 10 kGy), which indicates its high radiation stability.