Investigation and improvement of catalytic activity of G-quadruplex/hemin DNAzymes using designed terminal G-tetrads with deoxyadenosine caps,Chemical Science

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Investigation and improvement of catalytic activity of G-quadruplex/hemin DNAzymes using designed terminal G-tetrads with deoxyadenosine caps
Chemical Science ( IF 7.6 ) Pub Date : 2020-06-17 , DOI: 10.1039/d0sc01905d
Yanwei Cao _{1,

2,

3,

4,

5} , Pi Ding _{1,

2,

3,

4,

5} , Luyan Yang _{1,

2,

3,

4,

5} , Wenjing Li _{1,

2,

3,

4,

5} , Yu Luo _{1,

2,

3,

4,

5} , Jine Wang _{1,

2,

3,

4,

5} , Renjun Pei _{1,

2,

3,

4,

5}

Affiliation

It is generally acknowledged that G-quadruplexes (G4s) acquire peroxidase activity upon interaction with hemin. Hemin has been demonstrated to bind selectively to the 3′-terminal G-tetrad of parallel G4s via end-stacking; however, the relationships between different terminal G-tetrads and the catalytic functions of G4/hemin DNAzymes are not fully understood. Herein, the oligonucleotide d(AGGGGA) and its three analogues, d(AG^BrG^BrGGA), d(AG^BrGGG^BrA) and d(AG^BrGG^BrGA) (G^Br indicates 8-bromo-2′-deoxyguanosine), were designed. These oligonucleotides form three parallel G4s and one antiparallel G4 without loop regions. The scaffolds had terminal G-tetrads that were either anti-deoxyguanosines (anti-dGs) or syn-deoxyguanosines (syn-dGs) at different proportions. The results showed that the parallel G4 DNAzymes exhibited 2 to 5-fold higher peroxidase activities than the antiparallel G4 DNAzyme, which is due to the absence of the 3′-terminal G-tetrad in the antiparallel G4. Furthermore, the 3′-terminal G-tetrad consisting of four anti-dGs in parallel G4s was more energetically favorable and thus more preferable for hemin stacking compared with that consisting of four syn-dGs. We further investigated the influence of 3′ and 5′ deoxyadenosine (dA) caps on the enzymatic performance by adding 3′-3′ or 5′-5′ phosphodiester bonds to AG₄A. Our data demonstrated that 3′ dA caps are versatile residues in promoting the interaction of G4s with hemin. Thus, by increasing the number of 3′ dA caps, the DNAzyme of 3′A5′-5′GG3′-3′GG5′-5′A3′ with two 5′-terminal G-tetrads can exhibit significantly high catalytic activity, which is comparable to that of 5′A3′-3′GG5′-5′GG3′-3′A5′ with two 3′-terminal G-tetrads. This study may provide insights into the catalytic mechanism of G4-based DNAzymes and strategies for promoting their catalytic activities.

中文翻译：

使用设计的带有脱氧腺苷帽的末端G-四联体研究和提高G-四链体/血红素DNA酶的催化活性

通常公认的是，G-四链体（G4）与血红素相互作用后获得过氧化物酶活性。血红素已被证明可以通过末端堆叠选择性结合到平行G4的3'-末端G-四联体上。但是，尚未完全了解不同的末端G-四联体与G4 /血红素DNA酶的催化功能之间的关系。在本文中，所述寡核苷酸d（AGGGGA）和它的三个类似物，d（AG^溴ģ^溴GGA），d（AG^溴GGG^溴A）和d（AG^溴GG^溴GA）（G^溴表示8-溴-2'-脱氧鸟苷）。这些寡核苷酸形成三个没有环区域的平行G4和一个反平行G4。支架具有不同比例的末端G-四联体，其为抗脱氧鸟苷（抗-dGs）或顺-脱氧鸟苷（syn- dGs）。结果表明，平行的G4 DNAzyme表现出比反平行的G4 DNAzyme高2至5倍的过氧化物酶活性，这是由于在反平行的G4中不存在3'-端G-tetrad。此外，由四个平行于G4的抗-dG组成的3'-末端G- tetrad在能量上更有利，因此与由四个抗-dG组成的3-端G- tetrad相比，更优选syn -dGs。我们通过向AG ₄ A中添加3'-3'或5'-5'磷酸二酯键，进一步研究了3'和5'脱氧腺苷（dA）帽对酶促性能的影响。我们的数据表明3'dA帽是通用的残基促进G4与血红素的相互作用。因此，通过增加3'dA帽的数目，具有两个5'-末端G-四联体的3'A5'-5'GG3'-3'GG5'-5'A3'的DNA酶可以表现出显着的催化活性，与具有两个3'端G-四联体的5'A3'-3'GG5'-5'GG3'-3'A5'相当。这项研究可能提供有关基于G4的DNA酶的催化机制和促进其催化活性的策略的见解。

更新日期：2020-07-08

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