Abstract: Proteins in LEA5C（Group 5C Late Embryogenesis Abundant）family could involve in the responses to abiotic stresses and protect bio-macromolecules in cells from damages under abiotic stresses, due to their functions as molecular chaperones. The Deinococcus gobiensis I-0 isolated from Xinjiang Gobi Desert possessed highly strong resistance to ionizing radiation，oxidation，and desiccation. The genomic annotation of D. gobiensis I-0 indicated that Dgo_CA1605 encoding protein belonged to LEA5C family，named as Dgl5. Accordingly，the function of Dgl5 was investigated in this article. Recombinant expression strain Dgl5 was constructed by homologous recombination. The abiotic stress results revealed that Dgl5 significantly enhanced high-salt resistance of expression strain BL21 and maximally protected the host from the damages in freeze-thaw cycles. Likewise，the physiological and biochemical experiments in vitro demonstrated that the enzymatic activities of malate dehydrogenase and lactate dehydrogenase were effectively maintained due to Dg15 under freeze-thaw cycles. Therefore，we speculated that the improved resistance of the host adapting to harsh environment such as frozen and high-salt was achieved by Dg15 protecting cellular enzyme activities.

Key words: LEA5C, Deinococcus gobiensis I-0, abiotic stress, molecular chaperone