Figure 1. The TOXGREEN Assay.
(a) An overview of the ToxR-based assays. TM domain of interest is expressed as a ToxR-TM-MBP fusion protein which is biologically inserted into the inner membrane of E. coli. Upon dimerization of the TM region, ToxR will bind the ctx promoter and activate transcription of a reporter gene (lacZ, CAT, sfGFP). (b) TOXGREEN expression vector. The gene of the TOXCAT fusion is represented in red. The TM domain inserted at NheI and BamHI cut sites is highlighted in blue. The ctx promoter (magenta) and sfGFP reporter gene (green) are also shown.