Rapid molecular biosensing is an emerging application area for synthetic biology. Here, we engineer a portable biosensor for cyanuric acid (CYA), an analyte of interest for human and environmental health, using a LysR-type transcription regulator (LTTR) from Pseudomonas within the context of Escherichia coli gene expression machinery. To overcome cross-host portability challenges of LTTRs, we rationally engineered hybrid Pseudomonas-E. coli promoters by integrating DNA elements required for transcriptional activity and ligand-dependent regulation from both hosts, which enabled E. coli to function as a whole-cell biosensor for CYA. To alleviate challenges of whole-cell biosensing, we adapted these promoter designs to function within a freeze-dried E. coli cell-free system to sense CYA. This portable, on-demand system robustly detects CYA within an hour from laboratory and real-world samples and works with both fluorescent and colorimetric reporters. This work elucidates general principles to facilitate the engineering of a wider array of LTTR-based environmental sensors.

中文翻译：

---

用于便携式、按需检测三聚氰酸的转录生物传感器的设计。


快速分子生物传感是合成生物学的一个新兴应用领域。在这里，我们在大肠杆菌基因表达机制的背景下使用来自假单胞菌的 LysR 型转录调节因子 (LTTR) 设计了一种便携式氰尿酸 (CYA) 生物传感器，氰尿酸是人类和环境健康感兴趣的分析物。为了克服 LTTR 的跨宿主可移植性挑战，我们合理设计了杂交假单胞菌-E。通过整合来自两个宿主的转录活性和配体依赖性调节所需的 DNA 元件，使大肠杆菌启动子能够充当 CYA 的全细胞生物传感器。为了缓解全细胞生物传感的挑战，我们调整了这些启动子设计，使其在冻干大肠杆菌无细胞系统中发挥作用，以感知 CYA。这种便携式按需系统可在一小时内从实验室和实际样品中可靠地检测 CYA，并与荧光和比色报告仪配合使用。这项工作阐明了一般原则，以促进更广泛的基于 LTTR 的环境传感器的设计。