Fig. 1.
Pre-assembled OtpB promotes OtpA secretion. HDB114 transformed with pPC11 (PBAD-otpB) and pPC20 (Ptrc-otpA) were grown in minimal medium.
A. Cells were incubated with or without arabinose (ara) for the indicated time and cell (C) and secreted (S) fractions were analysed by Western blot using anti-OtpB.
B. Cells were incubated with or without arabinose for 30 min, washed three times and then incubated with IPTG for the indicated time. Cell and supernatant fractions were analysed by Western blot using anti-OtpA.
C. Cells were incubated with or without arabinose for 30 min, washed three times, incubated with IPTG for 10 min, and then subjected to pulse-chase labelling. OtpA was subsequently immunoprecipitated from cell and supernatant fractions.
D. Cells were incubated with arabinose for 30 min, washed three times, incubated with either IPTG or IPTG plus arabinose for 10 min, and then subjected to pulse-chase labelling. OtpB was subsequently immunoprecipitated from the cell fraction. m, molecular weight markers.