Identification of a specific inhibitor for DNA ligase I in human cells.
Identification of a specific inhibitor for DNA ligase I in human cells.
复制标题
鉴定人类细胞中 DNA 连接酶 I 的特异性抑制剂。
DOI：
10.1073/pnas.89.6.2227
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发表时间：
1992
影响因子：
11.1
通讯作者：
Chan,JY
中科院分区：
文献类型：
--
作者：
Yang,SW;Becker,FF;Chan,JY
最近发现了一种人类 DNA 连接酶 I 的蛋白质抑制剂。通过几个层析步骤将其与来自 HeLa 细胞的酶的一部分进行共纯化。该抑制剂首先通过相关酶不存在连接活性而被鉴定，同时它保留了形成连接酶-[32P]AMP 加合物的能力。抑制剂在约 0.25-0.30 M 氯化钠浓度下以单峰形式从 Mono S 柱中洗脱出来。它抑制纯化 DNA 连接酶 I 造成的双链和单链断裂的连接，但不抑制 T4 DNA 连接酶和 DNA 连接酶 II 造成的双链和单链断裂。随后的凝胶过滤层析表明，该抑制剂的分子量为55-75 kDa，可以与DNA连接酶I形成复合物并抑制DNA连接活性。在高盐条件下对连接酶 I-抑制剂复合物进行重色谱分析导致复合物解离并恢复酶活性，表明抑制剂与 DNA 连接酶 I 的物理相互作用是抑制机制之一。这些数据表明，这种 DNA 连接酶 I 的蛋白质抑制剂可能在复制、修复或重组过程中调节 DNA 连接中发挥特定作用。
A protein inhibitor for human DNA ligase I has recently been identified. It was copurified with a fraction of the enzymes from HeLa cells through several steps of chromatography. The inhibitor was first identified by the absence of ligation activity of the associated enzyme, while it retained the ability to form the ligase-[32P]AMP adducts. The inhibitor was eluted as a single peak at approximately 0.25-0.30 M NaCl from a Mono S column. It inhibited the ligation of both double-stranded and single-stranded breaks by purified DNA ligase I but not by T4 DNA ligase and DNA ligase II. Subsequent gel-filtration chromatography indicated that this inhibitor, with a molecular mass of 55-75 kDa, could form a complex with DNA ligase I and inhibited the DNA ligation activity. Rechromatography of the ligase I-inhibitor complex in high-salt conditions resulted in the dissociation of the complex and the restoration of enzyme activity, indicating that the physical interaction of inhibitor with DNA ligase I is one of the mechanisms of inhibition. These data indicate that this protein inhibitor for DNA ligase I may play a specific role in regulating DNA ligation during replication, repair, or recombination.