Fig. 2

Effects of different chaperones on HPV His₆-E6 expression levels. Representative immunoblots of induction and purification of HPV16 His₆-E6 produced in E. coli JM109. a Bacterial transformation with the pQE30-HPV16 His₆-E6 expression plasmid alone (w/o) or with the different chaperone systems (chaperones A–E, see Table 2). Total proteins were extracted by re-suspension in SDS-loading buffer of E. coli cell cultures, according to their OD₆₀₀. b Purification of the HPV16 His₆-E6 protein without chaperones (w/o) and with the trigger factor chaperone (with chaperones; chaperone E, see Table 2). M ColorBurst, Sigma, lanes 1 1 µL, lanes 2 3 µL, lane 3 C⁺, 20 ng of purified His₆-E6 protein positive control