Real-time azide or azido-functionalized molecular detection inside living cells using bioorthogonal chemistry-based approaches has been revolutionary to advancing chemical-biology. These methods have enabled diverse applications ranging from understanding the role of cellular glycosylation pathways, identifying diseased cells, and targeting delivery of azido-based therapeutic drugs. However, while classical techniques were applicable only to in-vitro detection of such functional groups, even recent bioorthogonal based-detection methods require expensive sensing reagents and also cannot selectively identify inorganic azide. Here, we report an in-vivo synthetic promoter based azide biosensor toolkit to selectively detect azide anions. A promiscuous cyanate-specific promoter was engineered to detect azide and rapidly induce expression of green fluorescent protein (GFP) in Escherichia coli. Our synthetic azide operon allows highly-tunable GFP expression, outperforming the classic lac-operon, and also offers an alternative low-cost protein expression system. Finally, we showcase the utility of this toolkit for in-vivo bioorthogonal reaction biosensing and glycoengineering based applications.

中文翻译：

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基于合成促进剂的叠氮化物生物传感器工具包可促进化学生物学

使用基于生物正交化学的方法对活细胞内部的叠氮化物或叠氮基官能化分子进行实时检测已成为推进化学生物学的革命性方法。这些方法实现了多种应用，包括了解细胞糖基化途径的作用，鉴定患病细胞以及靶向基于叠氮基的治疗药物。然而，尽管经典技术仅适用于此类官能团的体外检测，但即使是最近的基于生物正交的检测方法也需要昂贵的传感试剂，并且也不能选择性地鉴定无机叠氮化物。在这里，我们报告了一种基于体内合成促进剂的叠氮化物生物传感器工具包，可选择性检测叠氮化物阴离子。混杂的氰酸酯特异性启动子被工程化以检测叠氮化物并快速诱导绿色荧光蛋白（GFP）在大肠杆菌中的表达。我们的合成叠氮化物操纵子可以实现高度可调的GFP表达，优于经典的lac-操纵子，还提供了另一种低成本的蛋白质表达系统。最后，我们展示了该工具包在基于体内生物正交反应生物传感和糖工程的应用中的实用性。