Technical and Macromolecular Chemistry, Paderborn University, Warburger Str. 100, 33098, Paderborn, Germany.
Chembiochem. 2023 Jun 15;24(12):e202300338. doi: 10.1002/cbic.202300338. Epub 2023 May 17.
The stability of DNA origami nanostructures in aqueous media is closely tied to the presence of cations that screen electrostatic inter-helix repulsion. Here, the thermal melting behavior of different DNA origami nanostructures is investigated in dependence on Mg concentration and compared to calculated ensemble melting temperatures of the staple strands used in DNA origami folding. Strong deviations of the measured DNA origami melting temperatures from the calculated ones are observed, in particular at high ionic strength where the melting temperature saturates and becomes independent of ionic strength. The degree of deviation between the measured and calculated melting temperatures further depends on the superstructure and in particular the mechanical properties of the DNA origami nanostructures. This indicates that thermal stability of a given DNA origami design at high ionic strength is governed predominantly not by electrostatic inter-helix repulsion but mostly by mechanical strain.
DNA 折纸纳米结构在水介质中的稳定性与存在能够屏蔽螺旋间静电斥力的阳离子密切相关。在这里，研究了不同 DNA 折纸纳米结构的热融解行为对镁浓度的依赖性，并与用于 DNA 折纸折叠的短链的计算整体融解温度进行了比较。观察到测量的 DNA 折纸融解温度与计算值之间存在强烈的偏差，特别是在高离子强度下，融解温度饱和并变得与离子强度无关。测量值与计算值之间的偏差程度进一步取决于超结构，特别是 DNA 折纸纳米结构的机械性能。这表明，在高离子强度下，给定的 DNA 折纸设计的热稳定性主要不是由螺旋间的静电斥力决定，而是主要由机械应变决定。
