Background Whole cell biosensors provide a simple method for the detection of heavy metals. However, previous designs of them rely primarily on simulation of heavy metal resistance systems of bacteria. Results This study proposes a strategy for the rational design of metal detection circuits based on sensor proteins of the MerR family. Our results indicate the expression level of sensor protein can be used as a "rheostat" for tuning detection sensitivity with parabola curves to represent the relationships between the detection slopes and the sensor protein levels. This circuits design strategy (named as "Parabola Principle"), is used as a guide for the discovery of optimum metal detection circuits, and the design of biosensors with specific metal detection characteristics. For example, visible qualitative Hg (II) biosensors with a threshold of 0.05 mg/L are successfully constructed. Conclusions These results indicate the feasibility of developing a sensor that is much more tunable than what is presented. Graphical abstract

中文翻译：

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使用 MerR 家族蛋白的启动子作为“变阻器”来设计灵敏度可调的全细胞重金属生物传感器。

背景全细胞生物传感器为检测重金属提供了一种简单的方法。然而，它们以前的设计主要依赖于对细菌的重金属抗性系统的模拟。结果本研究提出了一种基于 MerR 家族传感器蛋白合理设计金属检测电路的策略。我们的结果表明，传感器蛋白的表达水平可以用作“变阻器”，用于调整检测灵敏度，用抛物线曲线表示检测斜率和传感器蛋白水平之间的关系。这种电路设计策略（称为“抛物线原理”）被用作发现最佳金属检测电路以及设计具有特定金属检测特性的生物传感器的指南。例如，成功构建了阈值为 0.05 mg/L 的可见定性 Hg (II) 生物传感器。结论 这些结果表明开发一种比所提出的更可调的传感器是可行的。图形摘要