Fig. 1

The PCA Biosensor in E. coli. a. Representation of the biosensor for detection of protocatechuic acid (PCA) is shown. Engineered chimeric promoter-operator (P_PV) inserted upstream from the eGFP reporter gene. PcaV binds to the promoter-operator sequence(s) repressing the expression of the reporter gene. Upon PCA binding to PcaV derepression occurs generating a fluorescent signal. b PCA biosensor dose response curves. eGFP gene expression data in the absence (empty shapes) and presence of the PcaV repressor (filled shapes), for the P_LV (red triangles) and P_PV (green squares) versions of the PCA biosensor in E. coli. c. Titration curves for active screened compounds using the P_PV version of the PCA biosensor in E. coli and their respective effector. The fluorescent gene expression normalized to cell density (RFU/OD₆₀₀) is shown relative to increasing concentrations of the effector. Each value represents the mean and standard deviation of 3 biological replicates