FIGURE 5.

SecB protects proOmpF and proOmpC from degradation by Lon in vitro. A, urea-denatured proOmpF (0.3 μm) was incubated with or without SecB₄ (1 μm) in the presence of Lon₆ (0.16 μm) and ATP as described under “Experimental Procedures.” Lon degradation of proOmpF was monitored after 2, 4, and 10 min of incubation, and the percentage of remaining proOmpF was quantified using OptiQuant software. B, degradation of denatured proOmpF (0.3 μm) by Lon₆ (0.16 μm) alone or in the presence of GrpE₂ (2 μm) or SecB₄ (1 μm) is shown. C, degradation of denatured proOmpC (0.3 μm) by Lon₆ (0.16 μm) alone or in the presence of SecB₄ (1 μm) is shown.