Abstract Deoxyribozymes (DNAzymes) are single-stranded DNA molecules that catalyze a broad range of chemical reactions. The 10–23 DNAzyme catalyzes the cleavage of RNA strands and can be designed to cleave essentially any target RNA, which makes it particularly interesting for therapeutic and biosensing applications. The activity of this DNAzyme in vitro is considerably higher than in cells, which was suggested to be a result of the low intracellular concentration of bioavailable divalent cations. While the interaction of the 10–23 DNAzyme with divalent metal ions was studied extensively, the influence of monovalent metal ions on its activity remains poorly understood. Here, we characterize the influence of monovalent and divalent cations on the 10–23 DNAzyme utilizing functional and biophysical techniques. Our results show that Na+ and K+ affect the binding of divalent metal ions to the DNAzyme:RNA complex and considerably modulate the reaction rates of RNA cleavage. We observe an opposite effect of high levels of Na+ and K+ concentrations on Mg2+- and Mn2+-induced reactions, revealing a different interplay of these metals in catalysis. Based on these findings, we propose a model for the interaction of metal ions with the DNAzyme:RNA complex.

中文翻译：

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一价金属离子对10-23脱氧核酶金属结合及催化活性的影响

摘要 脱氧核酶 (DNAzymes) 是单链 DNA 分子，可催化广泛的化学反应。10-23 DNAzyme 催化 RNA 链的切割，可以设计为基本上切割任何目标 RNA，这使得它在治疗和生物传感应用中特别有趣。这种脱氧核糖核酸酶在体外的活性远高于在细胞中的活性，这被认为是细胞内可生物利用的二价阳离子浓度低的结果。虽然 10-23 DNAzyme 与二价金属离子的相互作用被广泛研究，但一价金属离子对其活性的影响仍然知之甚少。在这里，我们利用功能和生物物理技术表征了单价和二价阳离子对 10-23 DNAzyme 的影响。我们的结果表明 Na+ 和 K+ 影响二价金属离子与 DNAzyme:RNA 复合物的结合，并显着调节 RNA 切割的反应速率。我们观察到高浓度 Na+ 和 K+ 对 Mg2+- 和 Mn2+ 诱导的反应的相反影响，揭示了这些金属在催化中的不同相互作用。基于这些发现，我们提出了金属离子与 DNAzyme:RNA 复合物相互作用的模型。