Abstract

Poly(ADP-ribose)polymerase 1 (PARP1) is involved in the processes of DNA repair, replication, transcription, cell cycle regulation, and apoptosis. Participation of PARP1 in DNA repair is determined by the ability of the enzyme to interact with various damages and noncanonical structures of DNA with consequent polyADP-ribosylation of neighboring proteins. Earlier, for mononucleosomes containing a DNA end recapitulating double-strand DNA break near the nucleosome, it was found that PARP1 induces nucleosome structural changes in the absence of NAD⁺. In the present work, it is reported that PARP1 induces similar structural changes in nucleosomes containing either DNA ends extending from the core by 20 bp or containing hairpins at the DNA ends. In all the cases, PARP1 caused changes in DNA wrapping on the surface of the histone octamer that are accompanied by an increase in the distance between adjacent DNA gyres. These PARP1-mediated changes in the nucleosome structure presumably contribute to chromatin decondensation and facilitate access of repair enzymes to damaged DNA.

中文翻译：

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PARP1绑定到DNA断裂和发夹改变了核小体的结构。

摘要

聚（ADP-核糖）聚合酶1（PARP1）参与DNA修复，复制，转录，细胞周期调节和凋亡的过程。PARP1是否参与DNA修复取决于酶与DNA的各种损伤和非规范结构相互作用的能力，其结果是邻近蛋白的polyADP-核糖基化。早先，对于含有在核小体附近重现双链DNA断裂的DNA末端的单核小体，发现PARP1在不存在NAD ⁺的情况下诱导核小体结构变化。。在目前的工作中，据报道，PARP1在包含从核心延伸20bp的DNA末端或在DNA末端包含发夹的核小体中诱导相似的结构变化。在所有情况下，PARP1都会导致组蛋白八聚体表面包裹的DNA发生变化，并伴随着相邻DNA回旋之间的距离增加。这些PARP1介导的核小体结构变化可能有助于染色质的缩合，并促进修复酶进入受损的DNA。