Fig. 4

Chaperone-assisted production of rHSA in E. coli. A, 12% SDS PAGE showing expression level of rHSA E. coli—in the absence of exogenous molecular chaperones (top panel), in the presence of GroEL–ES chaperone (middle panel) and in the presence of TF chaperone (bottom panel) with different duration of incubation after induction at Post induction incubation temperature of 18 °C. Lane 1 shows Uninduced fraction, Lane 2: 0 h, Lane 3: 1 h, Lane 4: 2 h, Lane 5: 3 h, Lane 6: 4 h, Lane 7: 5 h, Lane 8: 6 h, Lane 9: 7 h, Lane 10: 8 h, Lane 11: 9 h, Lane 12: 10 h, Lane 13: 11 h, Lane 14: 12 h, Lane BSA: BSA standard (~ 66 kDa). b Graph shows the expression level of rHSA when coexpressed in the presence and absence of exogenously employed molecular chaperone systems in E. coli. The expression level is depicted in terms of percentage of rHSA expressed in E. coli of the total expressed protein. Error bars represent standard error of the mean (SEM) with mean having 95% confidence limit. c Graph shows the relative expression level of rHSA at different incubation time in the presence (represented by black bars) and absence (represented in gray bars) of TF at 18 °C as depicted through their respective band intensities in the gel. In this analysis, the protein band corresponding to the sample collected at 2 h was selected as a reference band whose value was considered as unity and the band intensities of the remaining samples were normalized against it. Error bars represent standard error of the mean (SEM) having 95% confidence limit