Takao M, Yonemasu R, Yamamoto K, Yasui A
Department of Neurochemistry and Molecular Biology, Institute of Development, Ageing and Cancer, Tohoku University, Sendai, Japan.
Nucleic Acids Res. 1996 Apr 1;24(7):1267-71. doi: 10.1093/nar/24.7.1267.
From the fission yeast Schizosaccharomyces pombe, a cDNA fragment was isolated, which confers UV resistance on repair deficient Escherichia coli host cells. The cloned cDNA encodes a protein of 68,815 Da, which has a 36.6% identity of amino acid sequence with the previously identified 74 kDa UV endonuclease of the filamentous fungus Neurospora crassa. Analysis of several truncated gene constructs shows that only the C-terminal two thirds region, which has 54% identity of amino acid sequence with the C-terminal region of the Neurospora homolog, is necessary for complementing activity of UV-sensitivity in the E. coli host cells. Purified recombinant protein from E. coli host cells incises both UV-induced cyclobutane pyrimidine dimers and (6-4) photoproducts at the sites immediately 5' to the DNA damage in the same fashion as the Neurospora protein. Furthermore, a bacterial homologous sequence was isolated from Bacillus subtilis and shows a similar complementing activity of UV sensitivity in E. coli host cells, indicating a wide distribution of this alternative excision repair mechanism in life.
从裂殖酵母粟酒裂殖酵母中分离出一个cDNA片段，它能赋予修复缺陷型大肠杆菌宿主细胞紫外线抗性。克隆的cDNA编码一种68815 Da的蛋白质，其氨基酸序列与先前鉴定的丝状真菌粗糙脉孢菌74 kDa紫外线内切酶有36.6%的同一性。对几个截短的基因构建体的分析表明，只有C端三分之二区域（其氨基酸序列与脉孢菌同源物的C端区域有54%的同一性）对于在大肠杆菌宿主细胞中补充紫外线敏感性的活性是必需的。从大肠杆菌宿主细胞中纯化的重组蛋白以与脉孢菌蛋白相同的方式在DNA损伤紧邻的5'位点切割紫外线诱导的环丁烷嘧啶二聚体和（6-4）光产物。此外，从枯草芽孢杆菌中分离出一个细菌同源序列，它在大肠杆菌宿主细胞中显示出类似的紫外线敏感性补充活性，表明这种替代切除修复机制在生命中广泛分布。
