Fig. 2

Initial attempt at solubly expressing recombinant midgut proteases in SHuffle® T7 Express Competent E. coli cells (NEB). For each growth experiment, TB media and a 30 °C growth temperature was used. Cells were induced with 0.1 mM IPTG when reaching the log phase (OD_600nm ~ 0.5–1.0). Samples were collected at the given time points (in hours) and prepared for SDS-PAGE analysis. The MW ladder is in kilo-Daltons (kDa). In all cases, the arrow indicates where the expected soluble over-expressed protease should appear. However, all proteases under these conditions were expressed insolubly, only observed in the total samples. a 4–12% BIS-TRIS gel over-expression of AaET grown for a total of 26 h. The MW of the his₆-tagged AaET-NL zymogen is ~ 27.0 kDa. b 12% BIS-TRIS gel over-expression of AaSPVI grown for a total of 4 h. The MW of the his₆-tagged AaSPVI-NL zymogen is ~ 28.7 kDa. c 12% BIS-TRIS gel over-expression of AaSPVII grown for a total of 4 h. The MW of the his₆-tagged AaSPVII-NL zymogen is ~ 28.7 kDa. d 12% BIS-TRIS gel over-expression of AaLT grown for a total of 4 h. The MW of the his₆-tagged AaLT-NL zymogen is ~ 27.6 kDa