Repression of representative TTS proteins' expressions by robust induction of l0045. Plasmids were transformed into the wild-type (WT) EHEC strain and the expression was induced by adding IPTG. Assays of proteins present in the cell lysates and spent media were done similar to that described in legend to Fig. 2. Note: the expression strength of pQE60_L45 is higher than that of pACYC184_L45 used in Fig. 2. No repression of both synthesis and secretion of the LEE proteins was seen when an early termination was introduced at the 3rd codon of l0045. Repression was readily relieved with L45_E42A whose transglycosylase was inactivated due to a mutation created at the putative active site.