FIGURE 3.

HA tag insertion disrupts folding of D00. Intimin D00 and D00-HA domains were produced in E. coli either in the cytoplasm (top) or with a periplasmic export signal (bottom). The cells were lysed, and samples were taken from the lysate (L), the supernatant after centrifugation of the lysate (S), or the pellet after extracting twice with detergent (P). The panels on the left are Coomassie-stained gels after SDS-PAGE; the panels on the right are Western blots using an anti-StrepII antibody to detect the C-terminal StrepII tag of the constructs. Arrowheads show the presumed processed form of the protein with the signal peptide removed.