Processing oxidatively damaged bases at DNA strand breaks by APE1.
Processing oxidatively damaged bases at DNA strand breaks by APE1.
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DOI：
10.1093/nar/gkac695
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发表时间：
2022-09-09
影响因子：
14.9
通讯作者：
Freudenthal, Bret D.
中科院分区：
文献类型：
--
作者：
Whitaker, Amy M.;Stark, Wesley J.;Freudenthal, Bret D.
活性氧物种攻击DNA的结构，从而改变其碱基配对性质。因此，氧化应激相关的DNA损伤是导致癌症和其他疾病的突变负荷的主要来源。碱基切除修复(BER)是修复DNA碱基损伤的主要途径，脱嘌呤/脱嘧啶核酸内切酶(APE1)具有AP-内切酶和3‘-5’-外切核酸酶(Exo)的DNA切割功能。损伤的8-氧代-7，8-二氢鸟嘌呤(8-oxoG)可以作为直接损伤DNA的产物进入基因组，或者在复制或修复过程中通过在DNA链的3‘端插入聚合酶来进入基因组。重要的是，3‘-8-oxoG削弱了BER的连接步骤，因此必须通过替代酶的外源活性来去除，以防止双链断裂和细胞死亡。在本研究中，我们使用X射线结晶学来表征APE1在3‘-8-oxoG底物上的外向活性。这些结构支持统一的APE1exo机制，不同于其更规范的AP-内切酶活性。此外，通过用酶动力学和结合研究补充结构数据，使用野生型和合理设计的APE1突变体，我们能够鉴定和表征独特的蛋白质：特异性地介导APE1去除8-oxoG的DNA接触。
Reactive oxygen species attack the structure of DNA, thus altering its base-pairing properties. Consequently, oxidative stress-associated DNA lesions are a major source of the mutation load that gives rise to cancer and other diseases. Base excision repair (BER) is the pathway primarily tasked with repairing DNA base damage, with apurinic/apyrimidinic endonuclease (APE1) having both AP-endonuclease and 3′ to 5′ exonuclease (exo) DNA cleavage functions. The lesion 8-oxo-7,8-dihydroguanine (8-oxoG) can enter the genome as either a product of direct damage to the DNA, or through polymerase insertion at the 3′-end of a DNA strand during replication or repair. Importantly, 3′-8-oxoG impairs the ligation step of BER and therefore must be removed by the exo activity of a surrogate enzyme to prevent double stranded breaks and cell death. In the present study, we use X-ray crystallography to characterize the exo activity of APE1 on 3′-8-oxoG substrates. These structures support a unified APE1 exo mechanism that differs from its more canonical AP-endonuclease activity. In addition, through complementation of the structural data with enzyme kinetics and binding studies employing both wild-type and rationally designed APE1 mutants, we were able to identify and characterize unique protein: DNA contacts that specifically mediate 8-oxoG removal by APE1.
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影响因子：
16.8
作者：
Freudenthal BD;Beard WA;Cuneo MJ;Dyrkheeva NS;Wilson SH
通讯作者：
Wilson SH
发现聚合酶诱导的氧化核苷酸的细胞毒性。
影响因子：
64.8
作者：
Freudenthal, Bret D.;Beard, William A.;Perera, Lalith;Shock, David D.;Kim, Taejin;Schlick, Tamar;Wilson, Samuel H.
通讯作者：
Wilson, Samuel H.
影响因子：
2.9
作者：
He, Hongzhen;Chen, Qujia;Georgiadis, Millie M.
通讯作者：
Georgiadis, Millie M.
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
5.6
作者：
Brown, Jessica A.;Duym, Wade W.;Suo, Zucai
通讯作者：
Suo, Zucai