 A. TF-proOmpA physical interaction in solution. proOmpA1 (5 μM) was incubated (50 μl; Buffer C; < 0.2 M urea; 37°C; 60 min) with the indicated molar excess of TF2. Soluble proteins were analyzed on 10% native-PAGE (4 mA; 16h; 4°C) and Coomassie-blue stained. A representative experiment is shown; n= 4 biological replicates 