Apoptin's functional N- and C-termini independently bind DNA
Apoptin's functional N- and C-termini independently bind DNA
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DOI：
10.1016/s0014-5793(03)01465-0
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发表时间：
2004-01-16
期刊：
影响因子：
3.5
通讯作者：
Abrahams, JP
中科院分区：
文献类型：
--
作者：
Leliveld, SR;Dame, RT;Abrahams, JP
凋亡蛋白特异性地在肿瘤细胞中诱导凋亡，其中凋亡蛋白在DNA致密的异染色质和核仁中富集。在体外，Apoptin与dsDNA相互作用，形成可能与凋亡诱导相关的大核蛋白超结构。它的N-和C-末端结构域也具有细胞杀伤活性，尽管它们不如全长蛋白质有效。在这里，我们报告说，这两个凋亡素的N和C-末端的一半分别结合DNA，表明多个独立的结合位点。与全长Apoptin相比，两种截短突变体的细胞杀伤活性降低在体外通过亲和力降低反映出来。然而，没有一个截短突变体协同结合DNA或形成超结构，这表明凋亡素协同DNA结合是核蛋白超结构形成所必需的。由于Apoptin的N-和C-末端片段不仅具有凋亡活性，而且对DNA具有亲和力，因此我们认为这两种性质在功能上是相关的。(C)2003年欧洲生物化学学会联合会。Elsevier B. V.出版，保留所有权利。
Apoptin induces apoptosis specifically in tumour cells, where Apoptin is enriched in the DNA-dense heterochromatin and nucleoli. In vitro, Apoptin interacts with dsDNA, forming large nucleoprotein superstructures likely to be relevant for apoptosis induction. Its N- and C-terminal domains also have cell-killing activity, although they are less potent than the full-length protein. Here, we report that both Apoptin's Nand C-terminal halves separately bound DNA, indicating multiple independent binding sites. The reduced cell killing activity of both truncation mutants was mirrored in vitro by a reduced affinity compared to full-length Apoptin. However, none of the truncation mutants cooperatively bound DNA or formed superstructures, which suggests that cooperative DNA binding by Apoptin is required for the formation of nucleoprotein superstructures. As Apoptin's N- and C-terminal fragments not only share apoptotic activity, but also affinity for DNA, we propose that both properties are functionally linked. (C) 2003 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.