Six novel probes were prepared by covalent attachment of a G4‐DNA ligand (bis(quinolinium) pyridodicarboxamide; PDC) to various coumarin or pyrene fluorophores. In the absence of DNA, the fluorescence of all probes is quenched due to intramolecular photoinduced electron transfer (PET), as evidenced by photophysical and electrochemical studies, molecular modeling, and DFT calculations. All probes demonstrate similarly high thermal stabilization of various G4‐DNA substrates belonging to different folding topologies, as assessed by fluorescence melting experiments; however, their fluorimetric response is strongly heterogeneous with respect to the structures of the probes and G4‐DNA targets. Thus, the probes containing the 7‐diethylaminocoumarin fluorophore demonstrate significant fluorescence enhancement in the presence of G4‐DNA, with the strongest “light‐up” response (20‐ to 180‐fold) observed for antiparallel G4 structures as well as for hybrid G4 structures, formed by the variants of human telomeric sequence and capable of a conformation change to the antiparallel isoform. These results shed light on the influence of the linker and electronic properties of fluorophores on the efficiency of G4‐DNA “light‐up” probes operating via PET.

中文翻译：

---

基于光诱导电子转移的G-四链体DNA拓扑选择性荧光“照亮”探针

通过将G4-DNA配体（双（喹啉鎓）吡啶二甲酰胺; PDC）共价连接到各种香豆素或pyr荧光基团上制备了六种新颖的探针。在不存在DNA的情况下，由于分子内的光诱导电子转移（PET），所有探针的荧光都被淬灭，这一点已通过光物理和电化学研究，分子建模和DFT计算得到了证明。所有探针均显示出不同的G4-DNA底物具有相似的高热稳定性，这些底物属于不同的折叠拓扑结构，这是通过荧光熔解实验评估得出的；但是，它们的荧光响应在探针和G4-DNA靶标的结构上是高度异质的。因此，在存在G4-DNA的情况下，含有7-二乙基氨基香豆素荧光团的探针显示出显着的荧光增强，对反平行G4结构以及由人端粒序列变体形成的杂合G4结构观察到最强的“亮起”响应（20到180倍），并且能够构象改变为反平行同种型。这些结果揭示了荧光团的接头和电子性质对通过PET操作的G4-DNA“发光”探针效率的影响。