Figure 4

Time-resolved (TR) fluorescence counts of different concentrations of chicken ST6 expressed in Sf9 insect cells (0, 5, 20 and 50 μU/mL reaction) and of clarified lysates of bacterial cells expressing MBP-ST6. The bacterial strains used were DR611 and Origami 2 cells, without (pBAD33) or with co-expression of the molecular chaperones/co-chaperones trigger factor (Tig), DnaK/DnaJ (DnaK-J), GroEL/GroES (GroEL-ES), and ΔssSkp (Skp). Each sample of bacterial cell lysate contained equal number of cells. Experiments were carried out in replica triplicates and the error bars correspond to one standard deviation from the mean values. a.u.: arbitrary units; U: unit of sialyltransferase activity.