Figure 3.

Influence of CcmC abundance on cytochrome c maturation. Membrane fractions were prepared and analyzed as in Fig. 2. The strains in lanes 1–6 contained plasmid pEC409 expressing ccmC and ccmE. In lanes 7 and 8 the Δccm strain EC06 was complemented with pEC86 carrying ccmABCDEFGH and its ΔccmA mutant derivative pEC94, respectively. In addition, all strains contained pRJ3268 expressing the B. japonicum cycA gene encoding cytochrome c₅₅₀ (Cyt c₅₅₀). (A) Heme stain of membrane proteins (50 μg per lane). CcmE and NapC are indicated on the right. (B) Western blot of the same membrane protein fractions (30 μg per lane) as in A probed with anti-CcmE serum. (C) Heme stain of trichloroacetic acid-precipitated periplasmic proteins (20 μg in lanes 1–6 and 8; 3 μg in lane 7). NapB and cytochrome c₅₅₀ are indicated on the right.