Structural and Functional Characterization of a Unique AP Endonuclease From Deinococcus radiodurans.
Structural and Functional Characterization of a Unique AP Endonuclease From Deinococcus radiodurans.
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耐辐射奇球菌独特的 AP 核酸内切酶的结构和功能表征
DOI：
10.3389/fmicb.2020.01178
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发表时间：
2020
影响因子：
5.2
通讯作者：
Hua Y
中科院分区：
文献类型：
--
作者：
He Y;Wang Y;Qin C;Xu Y;Cheng K;Xu H;Tian B;Zhao Y;Wang L;Hua Y
各种内源性和外源性试剂引起DNA损伤，包括脱嘌呤/脱嘧啶（AP）位点。由于其细胞毒性作用，AP位点通常通过碱基切除修复（BER）途径被AP核酸内切酶切割。耐辐射异常球菌是一种特殊的耐辐射细菌，是研究DNA修复过程的理想模式生物。在此，我们研究了一个独特的AP内切酶（DrXth）从D。结果表明，该蛋白具有AP内切酶、3′-磷酸二酯酶、3′-磷酸酶和3′-5′外切核酸酶活性，但不具有核苷酸切口修复（NIR）活性。我们还发现，Mg 2+和Mn 2+是优选的二价金属内切酶和核酸外切酶的活动，分别。此外，使DrXth结晶，晶体衍射至1.5 nm。结构和生化分析表明，残基Gly 198是参与底物DNA结合和切割的关键残基。在D.抗辐射剂导致对DNA损伤剂的敏感性升高，并增加自发突变频率。总之，我们的研究结果表明，DrXth是一个重要的AP内切酶参与BER途径和功能与其他DNA修复酶，以维持基因组的稳定性。
Various endogenous and exogenous agents cause DNA damage, including apurinic/apyrimidinic (AP) sites. Due to their cytotoxic effects, AP sites are usually cleaved by AP endonuclease through the base excision repair (BER) pathway. Deinococcus radiodurans, an extraordinary radiation-resistant bacterium, is known as an ideal model organism for elucidating DNA repair processes. Here, we have investigated a unique AP endonuclease (DrXth) from D. radiodurans and found that it possesses AP endonuclease, 3′-phosphodiesterase, 3′-phosphatase, and 3′–5′ exonuclease but has no nucleotide incision repair (NIR) activity. We also found that Mg2+ and Mn2+ were the preferred divalent metals for endonuclease and exonuclease activities, respectively. In addition, DrXth were crystallized and the crystals diffracted to 1.5 Å. Structural and biochemical analyses demonstrated that residue Gly198 is the key residue involved in the substrate DNA binding and cleavage. Deletion of the drxth gene in D. radiodurans caused elevated sensitivity to DNA damage agents and increased spontaneous mutation frequency. Overall, our results indicate that DrXth is an important AP endonuclease involved in BER pathway and functions in conjunction with other DNA repair enzymes to maintain the genome stability.
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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
影响因子：
11.4
作者：
Gorman, MA;Morera, S;Freemont, PS
通讯作者：
Freemont, PS
有效修复耐辐射奇球菌自发性 DNA 损伤需要三个同源物
影响因子：
2.9
作者：
Hua, Xiaoting;Xu, Xin;Hua, Yuejin
通讯作者：
Hua, Yuejin
影响因子：
3.7
作者：
Félix RC;Silveira H
通讯作者：
Silveira H
DOI：
10.1107/s0907444909052925
发表时间：
2010-02
期刊：
Acta crystallographica. Section D, Biological crystallography
影响因子：
--
作者：
Adams PD;Afonine PV;Bunkóczi G;Chen VB;Davis IW;Echols N;Headd JJ;Hung LW;Kapral GJ;Grosse-Kunstleve RW;McCoy AJ;Moriarty NW;Oeffner R;Read RJ;Richardson DC;Richardson JS;Terwilliger TC;Zwart PH
通讯作者：
Zwart PH