Figure 1.

Requirements of ccm gene products for covalent incorporation of heme into CcmE. E. coli cells were grown anaerobically in the presence of nitrite. The Δccm mutant EC06 was complemented with plasmids expressing different combinations of ccmC, ccmD, and ccmE. (A) Activity stain for covalently bound heme of membrane protein fractions (50 μg per lane) separated by SDS/15% PAGE. (B) Western blot of the same membrane protein fractions (30 μg per lane) as in A probed with anti-CcmE serum. Lanes: 1, EC06 Δccm complemented with pEC410 (ccmE); 2, pEC406 (ccmCDE); 3, pEC408 (ccmDE); 4, pEC409 (ccmCE).