FIG. 6.

SDS-PAGE analysis of the fusion protein purified by the nickel chelate column. A 15% polyacrylamide separating gel and a 5% stacking gel were used for SDS-PAGE. The cell pellet from 1 ml of harvested culture medium was suspended in 100 μl of MilliQ water. The sample buffer (50 mM Tris-HCl [pH 8.0], 2% SDS, 5% 2-mercaptoethanol, 10% glycerol, 0.02% bromophenol blue) was added, and the mixture was heated for 5 min at 95°C. VBPs were separated in an electrophoretic cell for 1.5 h in running buffer (25 mM Tris, 192 mM glycine, 0.1% SDS). The gel was stained by silver. Lane 1, molecular mass marker; lane 2, proteins in purified inclusion body; lane 3, eluate from the nickel chelate column. The arrow indicates the position of the purified protein.