Figure 2

SDS-PAGE analysis of crude extracts obtained in comparative expression studies at 25°C. The three expression systems pET21d⁺, pBAD and pCOLD were optimally induced and cultivated for 20 h. One gram wet biomass of each cultivation was resuspended in 3 mL lysis buffer and lysed by the French Press. After centrifugation, 50 μl crude extracts were mixed with 50 μl Laemmli buffer, heated at 95°C for 5 min and 10 μl aliquots were analyzed by SDS-PAGE. Lane 1, molecular mass marker proteins; lane 2, pET21d⁺; lane 3, pCOLD; lane 4, pBAD; lane 5, molecular mass marker proteins.