背景:半胱氨酸(Cys),谷胱甘肽(GSH),和同型半胱氨酸(Hcy),因为三种主要的生物硫醇参与各种生理过程,在植物生长中起着至关重要的作用。Cys水平异常可导致植物不能正常生长。迄今为止,尽管已经报道了大量的荧光探针用于检测生物硫醇,由于它们的结构相似性,它们中很少能用于选择性区分Cys和GSH和Hcy,其中只有少数可用于植物成像。
结果:这里,构建了基于TMN荧光团和邻位/间位/对位取代马来酰亚胺识别基团的三种荧光探针(o-/m-/p-TMA),以研究Cys的选择性响应效应。与o/m-TMA相比,p-TMA可以相对于GSH和Hcy选择性检测Cys,具有快速的响应时间(10分钟)和低的检测限(0.26μM)。理论计算证实,与o/m-TMA-Cys(5.533/5.287)相比,中间p-TMA-Cys-int具有较短的原子间反应距离(3.827µ),使其更适合进一步的转环化反应。此外,p-TMA已用于使用单/双光子荧光成像选择性跟踪拟南芥中的外源和内源Cys。此外,单细胞壁产生明显的双光子荧光信号,表明p-TMA可用于单细胞中的高浓度Cys分析。令人惊讶的是,p-TMA可用作SDS-PAGE中蛋白质染色的荧光染料,其灵敏度(7.49μg/mL)高于经典考马斯亮蓝(14.11μg/mL)。
结论:p-TMA的出色特性使其成为一种有前途的多功能分子工具,用于在各种复杂环境中对GSH和Hcy进行高选择性Cys检测,包括水解决方案,斑马鱼,和植物。此外,它有可能被开发为一种简单,快速的SDS-PAGE荧光染色方法的荧光染料。
BACKGROUND: Cysteine (Cys), glutathione (GSH), and homocysteine (Hcy), as three major biothiols are involved in a variety of physiological processes and play a crucial role in plant growth. Abnormal levels of Cys can cause plants to fail to grow properly. To date, although a very large number of fluorescent probes have been reported for the detection of biothiols, very few of them can be used for the selective discrimination of Cys from GSH and Hcy due to their structural similarity, and only a few of them can be used for plant imaging.
RESULTS: Here, three fluorescent probes (o-/m-/p-TMA) based on TMN fluorophore and the ortho-/meta-/para-substituted maleimide recognition groups were constructed to investigate the selective response effect of Cys. Compared to the o-/m-TMA, p-TMA can selectively detect Cys over GSH and Hcy with a rapid response time (10 min) and a low detection limit (0.26 μM). The theoretical calculation confirmed that the intermediate p-TMA-Cys-int has shorter interatomic reaction distances (3.827 Å) compared to o-/m-TMA-Cys (5.533/5.287 Å), making it more suitable for further transcyclization reactions. Additionally, p-TMA has been employed for selective tracking of exogenous and endogenous Cys in Arabidopsis thaliana using both single-/two-photon fluorescence imaging. Furthermore, single cell walls produced obvious two-photon fluorescence signals, indicating that p-TMA can be used for high-concentration Cys analysis in single cells. Surprisingly, p-TMA can be used as a fluorescent dye for protein staining in SDS-PAGE with higher sensitivity (7.49 μg/mL) than classical Coomassie brilliant blue (14.11 μg/mL).
CONCLUSIONS: The outstanding properties of p-TMA make it a promising multifunctional molecular tool for the highly selective detection of Cys over GSH and Hcy in various complex environments, including water solutions, zebrafish, and plants. Additionally, it has the potential to be developed as a fluorescent dye for a simple and fast SDS-PAGE fluorescence staining method.