Fig. 7

Protein expression using antibiotic-based plasmid maintenance versus infA-based plasmid maintenance as shown by full cell lysates after induction of protein expression. a SDS PAGE showing samples obtained from a traditional protein expression culture using antibiotic-based plasmid maintenance. b SDS PAGE showing samples obtained from an antibiotic-free expression culture using infA complementation for plasmid maintenance. The model protein TNFα is 18.8 kDa. The protein marker (PM2500 ExcelBand™, SMOBIO Technology) is shown with the fragment sizes annotated on the gel in kDa