Recent advances in G-quadruplex (GQ) studies have provided evidence for their important role in key biological processes (replication, transcription, genome stability, and epigenetics). These findings imply highly specific interactions between GQ structures and cellular proteins. The details of the interaction between GQs and cellular proteins remain unknown. It is now accepted that GQ loop elements play a major role in protein recognition. It remains unclear whether and to what extent the GQ core contributes to maintaining the recognition interface. In the current paper, we used the thrombin binding aptamer as a model to study the effect of modification in the quadruplex core on the ability of aptamer to interact with thrombin. We used alpha-2′-deoxyguanosine and 8-bromo-2′-deoxyguanosine to reconfigure the core or to affect syn–anti preferences of selected dG-residues. Our data suggest that core guanines not only support a particular type of GQ architecture, but also set structural parameters that make GQ protein recognition sensitive to quadruplex topology.

中文翻译：

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凝血酶结合适体的识别接口需要四链体核心的反平行拓扑

G-四链体 (GQ) 研究的最新进展为其在关键生物过程（复制、转录、基因组稳定性和表观遗传学）中的重要作用提供了证据。这些发现暗示了 GQ 结构和细胞蛋白之间的高度特异性相互作用。GQs 和细胞蛋白之间相互作用的细节仍然未知。现在公认 GQ 环元件在蛋白质识别中起主要作用。目前尚不清楚 GQ 核心是否以及在多大程度上有助于维护识别界面。在本文中，我们以凝血酶结合适体为模型，研究了四链体核心中修饰对适体与凝血酶相互作用能力的影响。我们使用 alpha-2'-deoxyguanosine 和 8-bromo-2'-deoxyguanosine 重新配置核心或影响syn -所选 dG 残基的反偏好。我们的数据表明，核心鸟嘌呤不仅支持特定类型的 GQ 架构，而且还设置了使 GQ 蛋白识别对四链体拓扑结构敏感的结构参数。