Faculty of Pharmaceutical Sciences, Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida 194-8543, Japan.
Bioconjug Chem. 2023 Aug 16;34(8):1439-1446. doi: 10.1021/acs.bioconjchem.3c00220. Epub 2023 Aug 4.
In bioengineering, fluorescent amine-reactive probes are invaluable for the detection of amine species. In particular, targeting probes for lysine, which has a free amino group in amino acids, are a valid method for protein detection. For this purpose, many fluorescent "turn-on type" probes with amine reactivity have been developed; however, they require improvements. In the typical florescence probes, BODIPY and NBD analogs have small Stokes shifts based on absorption and emission and lability in an aqueous environment, respectively. In this study, a new class of fluorescent probes, , based on the electron push-pull-type 1,8-naphthyridine framework, was designed and investigated as an amine-reactive probe. Generally, electron push-pull-type fluorophores exhibit a large Stokes shift at the expense of fluorescent enhancement in aqueous media; thus, there is a trade-off between possessing a large Stokes shift and intense emission. However, reacts with primary amines, yielding emissive amine products with a large Stokes shift (>70 nm) without fluorescence quenching and side products, even in an aqueous environment, thereby overcoming the disadvantages of electron push-pull-type fluorophores and lability in aqueous conditions. By applying the specific features of , we achieved selective lysine detection and fluorescence bioimaging, such as endoplasmic reticulum-selective protein labeling and organelle staining, in living cells by utilizing amine-substituted derivatives.
在生物工程中，荧光胺反应探针对于检测胺类物质非常有价值。特别是针对赖氨酸的靶向探针，赖氨酸在氨基酸中具有游离氨基，是一种有效的蛋白质检测方法。为此，已经开发了许多具有胺反应性的荧光“开启型”探针；然而，它们需要改进。在典型的荧光探针中，BODIPY 和 NBD 类似物分别基于吸收和发射具有较小的斯托克斯位移，以及在水相环境中的不稳定性。在这项研究中，设计并研究了一类基于电子推挽型 1,8-萘啶骨架的新型荧光探针，作为胺反应探针。通常，电子推挽型荧光团以牺牲在水介质中荧光增强为代价，表现出较大的斯托克斯位移；因此，在具有较大斯托克斯位移和强烈发射之间存在权衡。然而，与伯胺反应，生成具有大斯托克斯位移（>70nm）的发荧光胺产物，而不会发生荧光猝灭和副产物，即使在水相环境中也是如此，从而克服了电子推挽型荧光团的缺点和水相条件下的不稳定性。通过利用 的特殊性质，我们实现了赖氨酸的选择性检测和荧光生物成像，例如内质网选择性蛋白标记和细胞器染色，这是通过利用胺取代衍生物在活细胞中实现的。
