Due to the potential toxicity of mercury, there is an immediate need to understand its uptake, transport and flux within living cells. Conventional techniques used to analyze Hg2+ are invasive, involve high cost and are less sensitive. In the present study, a highly efficient genetically encoded mercury FRET sensor (MerFS) was developed to measure the cellular dynamics of Hg2+ at trace level in real time. To construct MerFS, the periplasmic mercury-binding protein MerP was sandwiched between enhanced cyan fluorescent protein (ECFP) and venus. MerFS is pH stable, offers a measurable fluorescent signal and binds to Hg2+ with high sensitivity and selectivity. Mutant MerFS-51 binds with an apparent affinity (Kd) of 5.09 × 10-7 M, thus providing a detection range for Hg2+ quantification between 0.210 µM and 1.196 µM. Furthermore, MerFS-51 was targeted to Escherichia coli (E. coli), yeast and human embryonic kidney (HEK)-293T cells that allowed dynamic measurement of intracellular Hg2+ concentration with a highly responsive saturation curve, proving its potential application in cellular systems.

中文翻译：

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基于FRET的遗传编码光学传感器，用于活细胞中Hg2 +检测和细胞内成像。

由于汞的潜在毒性，迫切需要了解汞在活细胞内的吸收，迁移和通量。用于分析Hg2 +的常规技术具有侵入性，成本高且敏感性较低。在本研究中，开发了一种高效的遗传编码汞FRET传感器（MerFS），可以实时测量痕量水平的Hg2 +的细胞动力学。为了构建MerFS，将周质汞结合蛋白MerP夹在增强的蓝绿色荧光蛋白（ECFP）和金星之间。MerFS具有pH稳定性，可提供可测量的荧光信号，并以高灵敏度和选择性与Hg2 +结合。MerFS-51突变体以5.09×10-7 M的表观亲和力（Kd）结合，从而为Hg2 +定量提供了0.210 µM至1.196 µM的检测范围。此外，