The m6A methylation perturbs the Hoogsteen pairing-guided incorporation of an oxidized nucleotide,Chemical Science

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The m6A methylation perturbs the Hoogsteen pairing-guided incorporation of an oxidized nucleotide
Chemical Science ( IF 7.6 ) Pub Date : 2017-07-06 00:00:00 , DOI: 10.1039/c7sc02340e
Shaoru Wang _{1,

2,

3,

4,

5} , Yanyan Song _{1,

2,

3,

4,

5} , Yafen Wang _{1,

2,

3,

4,

5} , Xin Li _{1,

2,

3,

4,

5} , Boshi Fu _{1,

2,

3,

4,

5} , Yinong Liu _{1,

2,

3,

4,

5} , Jiaqi Wang _{1,

2,

3,

4,

5} , Lai Wei _{1,

2,

3,

4,

5} , Tian Tian _{1,

2,

3,

4,

5} , Xiang Zhou _{1,

2,

3,

4,

5}

Affiliation

Natural nucleic acid bases can form Watson–Crick (WC) or Hoogsteen (HG) base pairs. Importantly, 8-oxo-2′-deoxyguanosine (8-oxo-dG) in DNA or 8-oxo-dG 5′-triphosphate (8-oxo-dGTP) favors a syn conformation because of the steric repulsion between O8 and O4′ of the deoxyribose ring. 8-oxo-dGTP can be incorporated into DNA opposite the templating adenine (A) using HG pairing as the dominant mechanism. Both RNA and DNA can be methylated at the N6 position of A to form N⁶-methyladenine (m⁶A). It has been found that certain viral infections may trigger an increase in the production of both 8-oxo-dGTP and m⁶A. The current study aims to systematically explore the effects of m⁶A methylation on HG base pairs and the consequent nucleotide incorporation. Our thermodynamic melting study shows that the m⁶A·8-oxo-dG is significantly less stable than the A·8-oxo-dG base pair in the paired region of a DNA duplex. Moreover, we have used pre-steady-state kinetics to examine the incorporation of 8-oxo-dGTP opposite m⁶A relative to A by a variety of reverse transcriptase (RT) enzymes and DNA polymerase (DNA pol) enzymes such as the human immunodeficiency virus type 1 (HIV-1) RT and human DNA pol β. The results demonstrate that all of these enzymes incorporate 8-oxo-dGTP less efficiently opposite m⁶A relative to A. Considering the steric bulk of the purine–purine pair between 8-oxo-dG and A, m⁶A methylation may affect the HG pairing to a great extent. Hence, it will be unfavorable to incorporate 8-oxo-dGTP into the growing strand opposite m⁶A. Moreover, the impeded incorporation of 8-oxo-dGTP opposite m⁶A has been extended to determine m⁶A at pre-defined positions in human rRNA. Our study may provide new insights into the roles of m⁶A in reducing the mutagenic potential of cellular 8-oxo-dGTP.

中文翻译：

m ⁶ A甲基化干扰Hoogsteen配对指导的氧化核苷酸的掺入

天然核酸碱基可以形成Watson-Crick（WC）或Hoogsteen（HG）碱基对。重要的是，由于O8和O4'之间的空间排斥作用，DNA中的8-oxo-2'-脱氧鸟苷（8-oxo-dG）或8-oxo-dG 5'-三磷酸（8-oxo-dGTP）倾向于合成构象。的脱氧核糖环。可以使用HG配对作为主要机制，将8-oxo-dGTP掺入与模板腺嘌呤（A）相反的DNA中。RNA和DNA均可在A的N6位甲基化，形成N ^6-甲基腺嘌呤（m ⁶ A）。已经发现某些病毒感染可能会触发8-oxo-dGTP和m ⁶ A的产生增加。本研究旨在系统地研究m ⁶的作用。HG碱基对的甲基化和随后的核苷酸掺入。我们的热力学解链研究表明，在DNA双链体的配对区域中，m ⁶ A·8-氧代-dG的稳定性显着低于A·8-氧代-dG碱基对。此外，我们已使用稳态前动力学来研究通过多种逆转录酶（RT）酶和DNA聚合酶（DNA pol）酶（例如人）相对于A相对于m ⁶ A的8-oxo-dGTP的掺入1型免疫缺陷病毒（HIV-1）RT和人类DNA polβ。结果表明，相对于A，与m ⁶ A相对，所有这些酶掺入8-oxo-dGTP的效率均较低。考虑到8-oxo-dG与A之间的嘌呤-嘌呤对的空间体积，m ⁶甲基化可能在很大程度上影响HG配对。因此，不利的是将8-氧代-dGTP掺入与m ⁶ A相反的生长链中。此外，已将阻碍与m ⁶ A相对的8-氧-dGTP掺入以在预定位置确定m ^6A。在人类rRNA中。我们的研究可能会提供有关m ⁶ A在降低细胞8-oxo-dGTP诱变潜力中的作用的新见解。

更新日期：2017-07-22

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