Fig. 3

Cloning, expression, purification and Western blotting analysis of OmpF. aA PCR products of the ompF gene. Lane M1 Trans DNA Marker II (1500, 900, 700, 500, 400, 200 and 100 bp); lane 1 ompF PCR products. Lane 2 the recombinant pET-28a(+)-ompF plasmid. Lane 3 the recombinant pET-28a(+)-ompF plasmid digested with BamHI and XhoI; lane M2 Trans5K DNA Marker (5000, 3000, 2000, 1500, 1000, 800, 500 and 300 bp); B schematic representation of the pET-28a(+)-ompF plasmid; C SDS-PAGE analysis of the expression of rOmpF in auto-inducing media at different time. 1 mL of cultured cells were collected at 4, 6, 8, 10, 12, 14, and 24 h, respectively. Lane M protein marker (94.4–14.4 kDa); lane 1 4 h; lane 2 6 h; lane 3 8 h; lane 4 10 h; lane 5 12 h; lane 6 14 h; lane 7 24 h; D SDS-PAGE analysis of the purified rOmpF protein. Lane M 5 µL of protein marker (94.4–14.4 kDa); lane 1 total proteins after auto-induction of E. coli BL21 (DE3) containing pET-28a(+)-ompF (15 µL of cell lysis); lane 2 precipitation containing inclusion body after sonication and centrifugation (15 µL of renaturation solution); Lane 3 flowthrough (15 µL of elution solution); Lane 4 the eluent washed with 70% elution buffer (15 µL of the purified OmpF protein); E Western blotting analysis of the OmpF protein. Lane M, protein marker; lane 1, the OmpF protein