Cyclobutane pyrimidine dimers photolyase from extremophilic microalga: Remarkable UVB resistance and efficient DNA damage repair
Cyclobutane pyrimidine dimers photolyase from extremophilic microalga: Remarkable UVB resistance and efficient DNA damage repair
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来自极端微藻的环丁烷嘧啶二聚体光裂合酶：显着的 UVB 抗性和高效的 DNA 损伤修复
DOI：
10.1016/j.mrfmmm.2014.07.010
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发表时间：
2015-03-01
影响因子：
2.3
通讯作者：
Miao, Jinlai
中科院分区：
文献类型：
--
作者：
Li, Chongjie;Ma, Li;Miao, Jinlai
生活在南极地区的细菌已经发展出了一些适应极端条件下生长和生存的特征。衣藻（ice . Chlamydomonas sp. ice .）能很好地适应高水平的太阳紫外线辐射。在衣藻ICE-L转录组中发现了一个推测的光解酶。RACE-PCR获得完整的cDNA序列。该PHR编码包含579个氨基酸的多肽，具有明确的II类cpd光解酶特征，与莱茵衣藻（Chlamydomonas reinhardtii）高度同源（68%）。采用实时荧光定量PCR技术研究UVB暴露后潜在的DNA损伤和反应。在UVB照射6小时后，CPD光解酶mRNA表达水平增加了50倍以上。通过光解酶互补实验，我们发现在100 μ w/cm(2) UVB照射下，DNA光解酶使大肠杆菌SY2菌株的光修复能力增加了116倍以上。为了确定体外光解酶是否有活性，我们过表达CPD光解酶。结果表明，嘧啶二聚体在PHR2的作用下发生分裂。本研究报道了该酶的独特结构和高活性。这些发现有助于进一步了解光再活化的分子机制，并将加速光解酶在医学领域的应用。(C) 2015 Elsevier B.V.版权所有
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 6 h. Using photolyase complementation assay, we demonstrated that DNA photolyase increased photo-repair more than 116-fold in Escherichia coil strain SY2 under 100 mu w/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. (C) 2015 Elsevier B.V. All rights reserved.