Figure 2.

Effect of increasing amounts of apoTorC, apoTorC_C, and apoTorC_N on the torA–lacZ fusion activity. (A) β-Galactosidase activities of the torA–lacZ fusion of strain LCB512 (ΔtorC) producing either no apocytochrome (pBAD, ○), apoTorC (pBC, ●), apoTorC_N (pBC_N, □), apoTorC_C (pBC_C, ■), or TorC_C^C329S (pBC_C^C329S, ⋄) are expressed in Miller units. Strains were grown anaerobically with TMAO (10 mM); induction of the P_BAD promoter was performed with arabinose at the indicated concentrations. (B) Maturation state of TorC_C. Periplasmic fractions (60 μg) of LCB512 containing plasmid pBC_C grown as in A were loaded on an SDS/15% polyacrylamide gel. After electrophoresis, the gel was stained for heme with 3,3′,5,5′-tetramethylbenzidine (TMBZ) (1) or revealed by Western blotting with anti-His antibodies (2).