DNA photolyase from Antarctic marine bacterium Rhodococcus sp. NJ-530 can repair DNA damage caused by ultraviolet.

Marine bacterium Rhodococcus sp. NJ-530 has developed several ultraviolet (UV) adaptive characteristics for survival and growth in extreme Antarctic environment. Rhodococcus sp. NJ-530 DNA photolyase encoded by a 1146 bp photolyase-homologous region (phr) was identified in genome. Quantitative real-time PCR demonstrated that transcriptional levels of phr were highly up-regulated by ultraviolet-B (UV-B) radiation (90 μW·cm−2) and increased to a maximum of 149.17-fold after exposure for 20 min. According to the results of SDS-PAGE and western blot, PHR was effectively induced by isopropyl-β-d-1-thiogalactopyranoside (IPTG) at the genetically engineered BL21(DE3)-pET-32a( +)-phr construct under the condition of 15 °C for 16 h and 37 °C for 4 h. In terms of in vivo activity, compared with a phr-defective E. coli strain, phr-transformed E. coli exhibited higher survival rate under high UV-B intensity of 90 μW·cm−2. Meanwhile, the purified PHR, with blue light, presented obvious photorepair activity toward UV-induced DNA damage in vitro assays. To sum up, studying the mechanisms of Rhodococcus sp. NJ-530 photolyase is of great interest to understand the adaptation of polar bacteria to high UV radiation, and such data present important therapeutic value for further UV-induced human skin and genetic damage diseases.