Fig. 4

Comparison between the amounts of purified soluble fraction of protein in four E. coli hosts. a SDS-PAGE analysis of the purified protin, lane 1: negative control harboring empty pET22b, M: molecular weight marker (6.5 to 116 kDa), lanes 2 to 5: induced bacterial lysate in 2: Rosetta^TM 3: SHuffle^TM T7, 4: BL21^TM (DE3), and 5: Origami^TM (DE3); lanes 6 to 9: the purified recombinant anti-EpEX-scFv protein from soluble fractions 6: Rosetta^TM 7: SHuffle^TM T7, 8: BL21^TM (DE3), and 9: Origami^TM (DE3). b Quantitatively protein concentration assessment for soluble fractions after purification. The amount of soluble anti-EpEX-scFv produced by E. coli Rosetta^TM (DE3) strain and E. coli Origami^TM T7 was significantly lower than that expressed by BL21^TM (DE3). There was no significant difference between the soluble amounts produced by BL21^TM (DE3) and SHuffle^TM T7. Data were analyzed by unpaired, two-tailed Student’s t test and expressed as the mean ± SD of two experiments (**p < 0.01)