Premium
Escherichia coli ccm in‐frame deletion mutants can produce periplasmic cytochrome b but not cytochrome c
Author(s) -
Throne-Holst Mimmi,
Thöny-Meyer Linda,
Hederstedt Lars
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)00656-x
Subject(s) - periplasmic space , cytochrome b , cytochrome , chemistry , escherichia coli , mutant , cytochrome c , biochemistry , mitochondrion , gene , mitochondrial dna , enzyme
Escherichia coli CcmA, CcmB and CcmC polypeptides are required for cytochrome c synthesis and are thought to constitute the subunits of an ABC‐type transporter as judged from sequence data. Using a periplasmic reporter system based on Bacillus subtilis cytochrome c‐ 550 and E. coli cytochrome b ‐562 we show that the synthesis of the b ‐type cytochrome in the periplasm is normal in E. coli ccmA and ccmC in‐frame deletion mutants. Mutants deleted for ccmF or ccmG encoding a component of a putative cytochrome c ‐heme lyase and a membrane bound thioredoxin‐like protein, respectively, have the same phenotype. The ccm mutants produce cytochrome c ‐550 polypeptide, but not holocytochrome c . Taken together the results demonstrate that heme can be transported to the periplasm by a ccm ‐independent mechanism.