B. SecB protects proOmpA* from aggregation. proOmpA*1 (5 μM) was incubated (50 μl; Buffer C; 37°C; 60 min) alone or in the presence of the indicated molar excess of SecB4, and proOmpA* in the soluble fraction (after centrifugation) was analyzed by SDS-PAGE (as in Fig. 2C). Lane 2: 2.84 μg proOmpA*. Representative experiment shown; n= 4 biological replicates 