Figure 2.

A 0.1% SDS/15% polyacrylamide gel illustrating the purification of the bacterially produced FluA as a Strep-tag II fusion protein. Lane M, molecular size standard (masses labeled in kDa); lane 1, periplasmic protein extract of E. coli JM83 harboring pBBP21-FluA after overnight expression at 22°C; lane 2, flow-through of the streptavidin affinity column; lane 3, FluA eluted from the column; lane 4, BBP prepared in the same way after 3-h induction; lanes 5 and 6, as lanes 3 and 4 but without reduction of the disulfide bonds.