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. 2014 Jan 28;3(11):802–810. doi: 10.1021/sb400182x

Figure 4.

Figure 4

NIRW light-activated gene expression module. (A) Structure of a NIRW light-activated synthetic module. The DNA fragment encoding the c-di-GMP synthetic photocontrol module is ∼3.5 kb; the mrkH module is ∼0.8 kb. (B) Light-activated β-galactosidase activity in the E. coli T7 Express strain expressing a c-di-GMP-dependent MrkH transcription activator. Plates contained 0.008% arabinose, 0.015 mM IPTG, and 40 ug/mL X-gal. (C) β-galactosidase activities in liquid cultures grown in the dark or light to A600, ∼1.5. The medium contained 0.008% arabinose, 0.025 mM IPTG. Higher YhjH expression in the RBS3 construct abolished the undesired basal LacZ expression in the dark, whereas the RBS2 construct produced undesired LacZ expression in the dark. (D) Optimization of the photodynamic range of β-galactosidase levels by adjusting MrkH expression from the arabinose-inducible PBAD promoter. (E) Time-course of β-galactosidase levels. The E. coli T7 Express strain expressing the NIRW light-activated module with RBS3 was grown in LB medium containing 2 mM arabinose and 0.025 mM IPTG. (F) Growth curve of liquid cultures from panel E grown in the dark or light.