ABSTRACT
Bacterial biosensor strains can be useful tools for the discovery and characterization of antibacterial compounds. A plasmid-based reporter vector containing a transcriptional fusion between the
recA
promoter and green fluorescence protein gene was introduced into an
Escherichia coli
Δ
tolC
strain to create a biosensor strain that selectively senses inhibitors of DNA metabolism via the SOS response. The strain was used to develop a high-throughput assay to identify new inhibitors of DNA metabolism. Screening of the AstraZeneca compound library with this strain identified known inhibitors of DNA metabolism, as well as novel chemotypes. The cellular target of one novel series was elucidated as DNA gyrase through genetic characterization of laboratory-generated resistant mutants followed by 50% inhibitory concentration measurements in a DNA gyrase activity assay. These studies validated the use of this antibiotic biosensor strain to identify novel selective inhibitors of DNA metabolism by high-throughput screening.
摘要
细菌
生物传感器菌株是发现和鉴定抗菌化合物的有用工具。基于质粒的报告载体含有转录融合的
recA
启动子和绿色荧光蛋白
基因之间的转录融合。
大肠杆菌
Δ
tolC
菌株中引入了 recA 启动子和绿色荧光蛋白
基因,从而产生了一种
生物传感器菌株,它能通过 SOS 反应选择性地感知 DNA 代谢
抑制剂。该菌株被用于开发一种高通量检测方法,以鉴定新的 DNA 代谢
抑制剂。利用该菌株对
阿斯利康化合物库进行筛选,发现了已知的 DNA 代谢
抑制剂以及新型
化学物。通过对实验室产生的耐药突变体进行
基因鉴定,并在 DNA 回旋酶活性测定中测量 50%的抑制浓度,阐明了一种新型系列的细胞靶标是 DNA 回旋酶。这些研究验证了使用这种抗生素
生物传感器菌株通过高通量筛选来鉴定新型 DNA 代谢选择性
抑制剂的有效性。