title: Cyclobutane pyrimidine dimers photolyase from extremophilic microalga: remarkable UVB resistance and efficient DNA damage repair.
abstract: Bacteria living in the Antarctic region have developed several adaptive features for growth and survival under extreme conditions. Chlamydomonas sp. ICE-Lis well adapted to high levels of solar UV radiation. A putative photolyase was identified in the Chlamydomonas sp. ICE-L transcriptome. The complete cDNA sequence was obtained by RACE-PCR. This PHR encoding includes a polypeptide of 579 amino acids with clear photolyase signatures belonging to class II CPD-photolyases, sharing a high degree of homology with Chlamydomonas reinhardtii (68%). Real-time PCR was performed to investigate the potential DNA damage and responses following UVB exposure. CPD photolyase mRNA expression level increased over 50-fold in response to UVB radiation for 6h. Using photolyase complementation assay, we demonstrated that DNA photolyase increased photo-repair more than 116-fold in Escherichia coli strain SY2 under 100μw/cm(2) UVB radiation. To determine whether photolyase is active in vitro, CPD photolyase was over-expressed. It was shown that pyrimidine dimers were split by the action of PHR2. This study reports the unique structure and high activity of the enzyme. These findings are relevant for further understanding of molecular mechanisms of photo-reactivation, and will accelerate the utilization of photolyase in the medical field.
authors.affiliation: Key Laboratory of Marine Bioactive Substance, The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China.
authors.forename: Chongjie
authors.initials: C
authors.lastname: Li
authors.affiliation: Key Laboratory of Biofuels, and Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China.
authors.forename: Li
authors.initials: L
authors.lastname: Ma
authors.affiliation: Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China.
authors.forename: Shanli
authors.initials: S
authors.lastname: Mou
authors.affiliation: Key Laboratory of Marine Bioactive Substance, The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China. Electronic address: wangyibin@fio.org.cn.
authors.forename: Yibin
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Key Laboratory of Marine Bioactive Substance, The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Zheng
authors.affiliation: Key Laboratory of Marine Bioactive Substance, The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China.
authors.forename: Fangming
authors.initials: F
authors.lastname: Liu
authors.affiliation: Key Laboratory of Marine Bioactive Substance, The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China.
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Qi
authors.affiliation: Key Laboratory of Marine Bioactive Substance, The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China.
authors.forename: Meiling
authors.initials: M
authors.lastname: An
authors.affiliation: Key Laboratory of Marine Bioactive Substance, The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.affiliation: Key Laboratory of Marine Bioactive Substance, The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China; State Key Laboratory of Biological Fermentation Engineering of Beer (In Preparation), Qingdao, China. Electronic address: miaojinlai@163.com.
authors.forename: Jinlai
authors.initials: J
authors.lastname: Miao
mesh_terms: D000595:Amino Acid Sequence; D004260:DNA Repair; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000235:genetics / Q000502:physiology*; D058086:Microalgae / Q000201:enzymology*; D008969:Molecular Sequence Data; D011740:Pyrimidine Dimers / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D014466:Ultraviolet Rays
chemical_list: D011740:Pyrimidine Dimers; D004255:Deoxyribodipyrimidine Photo-Lyase
keywords: Chlamydomonas sp. ICE-L; Photo-reactivation; Photolyase; UV