DNA/RNA mimics of fluorescent proteins (DMFPs and RMFPs) have been exogenously screened for inspiring variant applications by specifically binding to chromophore analogues to activate their fluorescence. Considerable DMFPs and RMFPs form G-quadruplex (G4) or G4-like structures to accommodate FP chromophore analogues. Therefore, efforts ought to be made to investigate whether these FP chromophore analogues have distinctive interactions with endogenous G4 structures found in natural sequences, such as human telomeric G4s (htG4s). Herein, we found that htG4s can specifically interact with one of the hydroxyethylamino-benzylidene cyanophenyl chromophore derivatives (HBC514) to serve as DNA mimics of green FPs (DMGFPs). Importantly, Na⁺ is required to remodel the K⁺-favored hybrid htG4s into antiparallel htG4s-based DMGFPs with the synergic binding of HBC514. Furthermore, HBC514 most likely aggregates on DMGFPs into an AIEgen with suppressed intramolecular rotation to cause a 2 orders of magnitude enhancement in its fluorescence. Based on the Na⁺-specific DMGFPs, a selective Na⁺ sensor was developed with the potential to tolerate high K⁺ abundance using HBCs as the bifunctional G4-inducer and fluorescent reporter. The DMGFPs conquer the long-standing challenge of developing practical Na⁺ sensors that can be used in physiological environments (for example, serums) with a K⁺-instigated high G4 stability.

中文翻译：

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协同将人端粒 G-四链体协同重塑为 GFP 的 DNA 模拟物，具有 Na+ 选择性


荧光蛋白的 DNA/RNA 模拟物（DMFP 和 RMFP）已经过外源筛选，通过与发色团类似物特异性结合以激活其荧光来激发变体应用。相当多的 DMFP 和 RMFP 形成 G 四链体 （G4） 或类似 G4 的结构，以适应 FP 发色团类似物。因此，应努力研究这些 FP 发色团类似物是否与自然序列中发现的内源性 G4 结构（例如人类端粒 G4 （htG4s））具有独特的相互作用。在此，我们发现 htG4s 可以与一种羟乙基氨基-苄基氰基苯基发色团衍生物 （HBC514） 特异性相互作用，作为绿色 FPs （DMGFPs） 的 DNA 模拟物。重要的是，需要 Na ⁺ 将 K ⁺ 青睐的杂交 htG4 重塑为具有 HBC514 协同结合的基于反平行 htG4s 的 DMGFP。此外，HBC514 最有可能在 DMGFP 上聚集到 AIEgen 中，抑制分子内旋转，导致其荧光增强 2 个数量级。基于 Na ⁺ 特异性 DMGFP，开发了一种选择性 Na ⁺ 传感器，该传感器使用 HBC 作为双功能 G4 诱导子和荧光报告基因，有可能耐受高 K ⁺ 丰度。DMGFP 克服了开发实用 Na⁺ 传感器的长期挑战，这些传感器可用于具有 K⁺ 激发的高 G4 稳定性的生理环境（例如血清）。