CLONING AND EXPRESSION OF APE, THE CDNA-ENCODING THE MAJOR HUMAN APURINIC ENDONUCLEASE - DEFINITION OF A FAMILY OF DNA-REPAIR ENZYMES
CLONING AND EXPRESSION OF APE, THE CDNA-ENCODING THE MAJOR HUMAN APURINIC ENDONUCLEASE - DEFINITION OF A FAMILY OF DNA-REPAIR ENZYMES
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DOI：
10.1073/pnas.88.24.11450
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发表时间：
1991-12-01
影响因子：
11.1
通讯作者：
CHEN, DS
中科院分区：
文献类型：
--
作者：
DEMPLE, B;HERMAN, T;CHEN, DS
脱碱基（AP）位点是常见的，潜在的诱变性DNA损伤，被AP内切酶攻击。这些酶在后生动物中的生物学作用还没有被测试过。我们已经克隆了编码主要核AP内切酶的人cDNA（APE）。预测的猿蛋白，其中包含可能的核运输信号，是一个家庭的DNA修复酶，包括两个细菌AP核酸内切酶（外切A蛋白的肺炎链球菌和大肠杆菌的核酸外切酶III）和Rrp 1蛋白的果蝇的成员。纯化的Ape蛋白缺乏在细菌和果蝇酶中发现的针对未损伤DNA的3 '-外切核酸酶活性，但是缺乏解释这种差异的明显氨基酸变化表明，通过微调保守的活性位点进化出了各种酶功能。在AP核酸内切酶缺陷的E.大肠杆菌对DNA烷基化剂甲磺酸甲酯的杀伤具有显著的抗性。APE cDNA为分析这种中心酶在维持人类遗传稳定性中的作用提供了分子工具。
Abasic (AP) sites are common, potentially mutagenic DNA damages that are attacked by AP endonucleases. The biological roles of these enzymes in metazoans have not been tested. We have cloned the human cDNA (APE) that encodes the main nuclear AP endonuclease. The predicted Ape protein, which contains likely nuclear transport signals, is a member of a family of DNA repair enzymes that includes two bacterial AP endonucleases (ExoA protein of Streptococcus pneumoniae and exonuclease III of Escherichia coli) and Rrp1 protein of Drosophila melanogaster. Purified Ape protein lacks the 3'-exonuclease activity against undamaged DNA that is found in the bacterial and Drosophila enzymes, but the lack of obvious amino acid changes to account for this difference suggests that the various enzyme functions evolved by fine tuning a conserved active site. Expression of the active human enzyme in AP endonuclease-deficient E. coli conferred significant resistance to killing by the DNA-alkylating agent methyl methanesulfonate. The APE cDNA provides a molecular tool for analyzing the role of this central enzyme in maintaining genetic stability in humans.