School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan, 453007, China.
School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan, 453007, China.
Talanta. 2020 Nov 1;219:121287. doi: 10.1016/j.talanta.2020.121287. Epub 2020 Jun 13.
Selenocysteine (Sec, pK 5.8) is genetically encoded 21st amino acid into the active site of selenoproteins, which have broad functions relevant to various diseases, tissues or organs and subcellular organelles. However, many selenoproteins involved cellular functions still remains unclear. In addition, since biothiols such as glutathione (GSH, pK 8.3), possessing similar chemical properties with Sec, commonly exist in living systems at high levels. Thus, it is of great importance and high challenge to identify novel probes for selectively monitoring Sec over biothiols. In this paper, we proposed a smart strategy which allowed us to develop a lysosome targetable probe for specifically sensing Sec. By restricting weak acidic microenvironment, the probe shows a specific detection for Sec with 85-fold fluorescence enhancement owing to the remaining high activity of Sec at pH 5.0. Moreover, being low cytotoxicity to the cells verified by MTS assay, the probe was then successfully applied for imaging exogenous and endogenous Sec in lysosomes, indicating its potential for the biological investigation of Sec in subcellular organelles.
硒代半胱氨酸（Sec，pK 5.8）是一种遗传编码的 21 号氨基酸，进入硒蛋白的活性部位，具有广泛的功能，与各种疾病、组织或器官以及亚细胞细胞器有关。然而，许多涉及细胞功能的硒蛋白的作用机制仍然不清楚。此外，由于生物硫醇（如谷胱甘肽（GSH，pK 8.3））在活细胞中以高浓度存在，并且具有与 Sec 相似的化学性质。因此，开发用于选择性监测 Sec 相对于生物硫醇的新型探针具有重要意义和挑战。在本文中，我们提出了一种智能策略，使我们能够开发一种用于特异性检测 Sec 的溶酶体靶向探针。通过限制弱酸性微环境，探针在 pH 5.0 时仍能保持高活性，对 Sec 具有特异性检测，荧光增强 85 倍。此外，通过 MTS 测定证实了对细胞的低细胞毒性，该探针随后成功地用于溶酶体中外源和内源性 Sec 的成像，表明其在亚细胞细胞器中研究 Sec 的生物学特性方面具有潜力。
