Figure 4

Expression and purification of the HBsAg(S)-GST fusion protein. (A) Schematic diagram showing the DNA region cloned in pRP-HBsAg(S)-GST and the sizes of the predicted encoded protein. The map in this figure was generated using the BioEdit software (Ibis Biosciences, USA). (B) An image of a Coomassie blue-stained SDS-PAGE gel of cell lysates of E. coli strains carrying the pRP-HBsAg(S)-GST that were either not induced with IPTG (-) or induced with 1 mM IPTG for 3 hours (+). The first lane contained protein molecular weight marker (BioRad, USA) and the sizes of the respective bands is indicated on the left side of the panel. (C) An image of a Coomassie blue-stained SDS-PAGE gel of purified HBsAg(S)-GST fusion protein. The first lane contained protein molecular weight marker (Fermentas, USA) and the sizes of the respective bands is indicated on the left side of the panel. Lane 2 contained a sample of the column flow through (FT), lane 3 contained a sample of the column wash (W), while lanes 5-8 contain samples of the fractions eluted from the GST column. The arrow indicates the position of the main component eluted from the column with a band size of approximately 52 kDa.