MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-Sen University, Guangzhou, 510275, P. R. China.
Angew Chem Int Ed Engl. 2020 Jun 8;59(24):9719-9726. doi: 10.1002/anie.202002422. Epub 2020 Apr 1.
G-quadruplex DNA show structural polymorphism, leading to challenges in the use of selective recognition probes for the accurate detection of G-quadruplexes in vivo. Herein, we present a tripodal cationic fluorescent probe, NBTE, which showed distinguishable fluorescence lifetime responses between G-quadruplexes and other DNA topologies, and fluorescence quantum yield (Φ ) enhancement upon G-quadruplex binding. We determined two NBTE-G-quadruplex complex structures with high Φ values by NMR spectroscopy. The structures indicated NBTE interacted with G-quadruplexes using three arms through π-π stacking, differing from that with duplex DNA using two arms, which rationalized the higher Φ values and lifetime response of NBTE upon G-quadruplex binding. Based on photon counts of FLIM, we detected the percentage of G-quadruplex DNA in live cells with NBTE and found G-quadruplex DNA content in cancer cells is 4-fold that in normal cells, suggesting the potential applications of this probe in cancer cell detection.
G-四链体 DNA 表现出结构多态性，这使得在体内准确检测 G-四链体时，使用选择性识别探针变得具有挑战性。在此，我们提出了一种三足阳离子荧光探针 NBTE，它在 G-四链体和其他 DNA 拓扑结构之间表现出可区分的荧光寿命响应，并且在与 G-四链体结合时荧光量子产率（Φ）增强。我们通过 NMR 光谱确定了两个具有高 Φ 值的 NBTE-G-四链体复合物结构。这些结构表明，NBTE 通过 π-π 堆积与 G-四链体通过三个臂相互作用，这与与双链 DNA 用两个臂相互作用不同，这解释了 NBTE 与 G-四链体结合时更高的 Φ 值和寿命响应。基于 FLIM 的光子计数，我们用 NBTE 检测了活细胞中 G-四链体 DNA 的百分比，发现癌细胞中的 G-四链体 DNA 含量是正常细胞的 4 倍，这表明该探针在癌细胞检测中的潜在应用。
