Figure 2.

DBL2-X and DBL3-X expression in E. coli and purification. a. Electrophoresis in an SDS 12% polyacrylamide gel of aliquots from different steps in expression, refolding and purification of DBL3-X. Lane 1, non-induced BL21 (DE3) (containing pET24a-DBL3-X plasmid); lane 2, induced BL21 (DE3) containing the pET24a-DBL3-X plasmid; lane 3, inclusion bodies suspension; lane 4, inclusion bodies after washing and denaturation in Urea 8 M; lane 5, affinity column flow through; lane 6, portion of DBL3-X lost during refolding onto the affinity column; lane 7, affinity column elution pool; lane 8, molecular size exclusion column purified DBL3-X. b. Electrophoresis of refolded DBL3-X in a SDS 12% polyacrylamide gel before (-) and after (+) reduction with dithiothreitol (DTT). c. Electrophoresis of refolded DBL2-X in a SDS 12% polyacrylamide gel before (-) and after (+) reduction with dithiothreitol (DTT). Higher mobility before reduction indicates the presence of disulfide linkages.