Fig. 4. Folded HasA inhibits its own secretion. Strain LMD439 (hasDE under arabinose control) carrying the plasmid pLMD485 (hasA under IPTG control) was grown on LB (A) or LB with 0.02% arabinose (B). When the OD₆₀₀ reached 0.1, these cultures were aliquoted into flasks containing various amounts of IPTG and grown for 3 h. Proteins present in supernatants (even lanes) and cell pellets (odd lanes) were visualized after separation on 14% polyacrylamide gels and staining with Coomassie Blue. An OD₆₀₀ equivalent of 0.2 was loaded in each lane.