Fig 5.

Western blot detection of the IFN-α2b protein when the respective gene was expressed either with pelB, celB₂₃ (23 indicates the number of codons), or the optimized celB_D11 fusion. Expression of ifn-a2b_S without any fusion did not lead to detectable protein (IFN-α2b). The genes were expressed in E. coli production strain RV308. Cell samples were lysed by sonication, and the total crude cell extracts were subjected to analysis. HisProbe-HRP was used for specific detection of the fusion proteins. For IFN-α2b proteins containing pelB, celB₂₃, or celB_D11 fusions, dilution series of decreasing total protein amounts were loaded; 1 corresponds to 10 μg. The size of PelB–IFN-α2b–c-Myc–His₆ is 24.4 kDa and of CelB₂₃–IFN-α2b–c-Myc–His₆ and CelB_D11–IFN-α2b–c-Myc–His₆ is 24.9 kDa, while the protein complex without an N-terminal fusion peptide is 22.4 kDa.