Fig. 1. Expression of SC binding peptide in E. coli is toxic. (A) E. coli BL21 (DE3) pLysS cells were transformed with either pET-M30, pET-M30-8F or pET-M30-8A vectors expressing His-GST, and respectively the 8F SC binding peptide (MGPRQLDLF) or the SC non-binding mutant 8A (MGPRALDAA) in fusion with His-GST. After 1 hour incubation at 37 °C, one tenth of the transformation mixtures were plated on LB agar plates containing kanamycin, chloramphenicol and either 0 or 0.1 mM IPTG. The picture was taken after 18 hours incubation at 37 °C. (B) The growth of transformed E. coli BL21 (DE3) pLys cells in Luria broth complemented or not with IPTG was followed over a period of 5 h 30 min by measurement of OD₆₀₀ every 15 minutes in a TECAN M200 plate reader. Open symbols: no IPTG in the medium; closed symbols: 0.5 mM IPTG; circles: empty vector (pETM30); squares: expression of SC non binding peptide (pETM30-8A); triangles: expression of SC binding peptide (pETM30-8F).