Capturing snapshots of APE1 processing DNA damage.
Capturing snapshots of APE1 processing DNA damage.
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DOI：
10.1038/nsmb.3105
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发表时间：
2015-11
影响因子：
16.8
通讯作者：
Wilson SH
中科院分区：
文献类型：
--
作者：
Freudenthal BD;Beard WA;Cuneo MJ;Dyrkheeva NS;Wilson SH
DNA脱嘌呤-脱嘧啶（AP）位点是基因组稳定性的普遍非编码威胁，并由AP内切酶1（APE 1）加工。APE 1切割AP位点磷酸二酯骨架，产生具有潜在细胞毒性的DNA修复中间体。切割反应的分子事件仍然难以捉摸，部分原因是有限的结构信息。我们报告了多个高分辨率的人类APE 1：DNA结构，揭示了APE 1反应的新特征，包括金属结合位点，亲核试剂和精氨酸夹介导的产物释放。我们还报告了APE 1：DNA结构与AP位点5′端的T：G错配，代表甲基化CpG二核苷酸中发生的簇状损伤。这些结果表明，APE 1将T：G错配塑造成独特的Watson-Crick样几何结构，使活动部位变形，从而减少切口。这些快照提供了APE 1的机制清晰度，同时提供了一个合理的框架来操纵DNA损伤的生物反应。
DNA apurinic-apyrimidinic (AP) sites are prevalent non-coding threats to genomic stability and are processed by AP endonuclease 1 (APE1). APE1 incises the AP-site phosphodiester backbone, generating a DNA repair intermediate that is potentially cytotoxic. The molecular events of the incision reaction remain elusive due in part to limited structural information. We report multiple high-resolution human APE1:DNA structures that divulge novel features of the APE1 reaction, including the metal binding site, nucleophile, and arginine clamps that mediate product release. We also report APE1:DNA structures with a T:G mismatch 5′ to the AP-site, representing a clustered lesion occurring in methylated CpG dinucleotides. These reveal that APE1 molds the T:G mismatch into a unique Watson-Crick like geometry that distorts the active site reducing incision. These snapshots provide mechanistic clarity for APE1, while affording a rational framework to manipulate biological responses to DNA damage.