Excision of products of oxidative DNA base damage by human NTH1 protein
Excision of products of oxidative DNA base damage by human NTH1 protein
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DOI：
10.1021/bi9819071
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发表时间：
1999-01-05
期刊：
影响因子：
2.9
通讯作者：
Roldán-Arjona, T
中科院分区：
文献类型：
--
作者：
Dizdaroglu, M;Karahalil, B;Roldán-Arjona, T
大肠杆菌内切核酸酶III（nth-Eco蛋白）的功能性人同源物最近已被克隆和表征[Aspinwall，R.，Rothwell，D. G.，Roldan-Arjona，T.，Anselmino，C.，沃德角，澳-地J.，Cheadle，J. P.，桑普森，J.R.，Lindahl，T.，哈里斯，宾夕法尼亚州，和希克森，我。D.等人（1997）Proc. Acad. Sci.美国，94，109-114]。这种酶，命名为hNTH 1蛋白，与Nth-Eco蛋白和来自粟酒裂殖酵母的相关酶（Nth-Spo蛋白）具有广泛的序列相似性。我们研究了底物特异性的这种人类酶的氧化DNA碱基损伤，使用气相色谱/同位素稀释质谱技术。使用了四种不同的DNA底物，其被各种自由基产生系统破坏。5-羟基胞嘧啶、胸腺嘧啶乙二醇、5-羟基-6-羟基胸腺嘧啶、5，6-二羟基胞嘧啶和5-羟基尿嘧啶是在DNA底物中发现的17个损伤中hNTH 1蛋白的底物。底物特异性和切除动力学的人类酶被发现是显着不同的Nth-Spo和Nth-Eco蛋白。
A functional human homologue of Escherichia coli endonuclease III (nth-Eco protein) has recently been cloned and characterized [Aspinwall, R., Rothwell, D. G., Roldan-Arjona, T., Anselmino, C., Ward, C. J., Cheadle, J. P., Sampson, J. R., Lindahl, T., Harris, P. C., and Hickson, I. D. (1997) Proc. Natl. Acad. Sci. U.S.A., 94, 109-114]. This enzyme, designated hNTH1 protein, shares an extensive sequence similarity with Nth-Eco protein and a related enzyme from Schizosaccharomyces pombe (Nth-Spo protein). We investigated the substrate specificity of this human enzyme for oxidative DNA base damage, using the technique of gas chromatography/isotope-dilution mass spectrometry. Four different DNA substrates damaged by various free radical-generating systems were used. 5-Hydroxycytosine, thymine glycol, 5-hydroxy-6-hydrothymine, 5,6-dihydroxycytosine, and 5-hydroxyuracil were substrates of hNTH1 protein among 17 lesions found in DNA substrates. The substrate specificity and excision kinetics of the human enzyme were found to be significantly different from those of Nth-Spo and Nth-Eco proteins.