The possibility to target noncanonical guanine structures with specific ligands for therapeutic purposes inspired numerous theoretical and experimental investigations of a guanine quartet and its stacked composites. In this work, we employed the interacting quantum atoms methodology to study interactions among different fragments in complexes composed of a guanine quartet and alkali (Li⁺, Na⁺, K⁺) or alkaline earth (Be²⁺, Mg²⁺, Ca²⁺) cations in vacuo: metal–quartet interaction, influence of the cation on guanine–guanine interaction, as well as hydrogen bond cooperativity in the guanine quartet and its complexes with metal ions. Interestingly, although the presence of a cation intensifies interaction among guanine molecules, it lowers their binding energy because of notable quartet’s distortion which is responsible for guanines’ substantial deformation energy. This phenomenon is particularly pronounced with Be²⁺ which, out of the six analyzed cations, enhances hydrogen bond cooperativity to the greatest extent.

中文翻译：

---

鸟嘌呤四方配合物与碱和碱土阳离子的有趣分子间相互作用

靶向具有治疗目的的特定配体的非规范鸟嘌呤结构的可能性激发了对鸟嘌呤四重体及其堆叠复合物的众多理论和实验研究。在这项工作中，我们采用相互作用的量子原子方法研究鸟嘌呤四重体与碱（Li ⁺，Na ⁺，K ⁺）或碱土（Be 2 ⁺，Mg ^{2 +}，Ca ²）组成的配合物中不同片段之间的相互作用⁺）真空中的阳离子：金属-四重态相互作用，阳离子对鸟嘌呤-鸟嘌呤相互作用的影响以及鸟嘌呤四重体及其与金属离子络合物中的氢键协同作用。有趣的是，尽管阳离子的存在增强了鸟嘌呤分子之间的相互作用，但由于显着的四重态畸变导致鸟嘌呤的大量形变能，它降低了它们的结合能。这种现象在Be ^2+中尤为明显，在6种被分析的阳离子中，Be ²⁺在最大程度上增强了氢键的协同作用。