Selective inhibitors of terminal deoxyribonucleotidyltransferase (TdT): Baicalin and genistin
Selective inhibitors of terminal deoxyribonucleotidyltransferase (TdT): Baicalin and genistin
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DOI：
10.1016/j.bbagen.2005.06.017
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发表时间：
2005-10-10
影响因子：
3
通讯作者：
Sakaguchi, K
中科院分区：
文献类型：
--
作者：
Uchiyama, Y;Tagami, J;Sakaguchi, K
哺乳动物末端脱氧核糖核苷基转移酶（TdT）的研究通过使用选择性地降低酶活性的抑制剂来促进。我们筛选了选择性TdT抑制剂，并在日本蔬菜牛蒡中发现了一种具有这种特性的天然化合物。该化合物对α、β、δ、λ等哺乳动物DNA聚合酶和Taq、T4、Klenow片段等原核生物DNA聚合酶活性影响不大。H-1和c -13核磁共振光谱分析表明该化合物为黄芩苷，一种以前被报道为抗炎或解热剂的化合物。黄芩苷对TdT的IC50值为18.6 μ M，我们还发现黄芩苷衍生物genistin具有抗诱变作用，虽然IC50值较黄芩苷弱（28.7 μ M），但其选择性抑制TdT活性的能力强于黄芩苷。Genistin和黄芩苷还抑制了截断的TdT（所谓的pol β核心结构域）的活性，其中BRCT基序在其n端区域被删除。在动力学分析中，黄芩苷和genistin对dNTP的抑制作用与引物具有竞争性，而与底物无竞争性。因此，这些化合物可能直接结合到TdT的引物结合位点，同时干扰dNTP底物与引物的结合。Genistin和黄芩苷应被证明是研究TdT的有用药物。(c) 2005 Elsevier B.V.版权所有
Studies of mammalian terminal deoxyribonucleotidyltransferase (TdT) are facilitated by use of inhibitors that selectively knock down the activity of the enzyme. We have screened for selective inhibitors of TdT and identified a natural compound with this property in the Japanese vegetable, Arctium lappa. The compound has little effect on the activities of mammalian DNA polymerases, such as alpha, beta, delta or lambda polymerase, and prokaryotic DNA polymerases, such as Taq DNA polymerase, T4 DNA polymerase and Klenow fragment. H-1- and C-13-NMR spectroscopic analyses showed the compound to be baicalin, a compound previously reported as an anti-inflammatory or antipyretic agent. The IC50 value of baicalin to TdT was 18.6 mu M. We also found that genistin, a baicalin derivative known to be antimutagenic, more selectively inhibited TdT activity than baicalin, although its IC50 value was weaker (28.7 mu M). Genistin and baicalin also inhibited the activity of truncated TdT (the so-called pol beta core domain) in which the BRCT motif was deleted in its N-terminal region. In kinetic analyses, inhibition by either genistin or baicalin was competitive with the primer and non-competitive with the dNTP substrate. The compounds may, therefore, bind directly to the primer-binding site of TdT and simultaneously disturb dNTP substrate incorporation into the primer. Genistin and baicalin should prove to be useful agents for studying TdT. (c) 2005 Elsevier B.V. All rights reserved.