Soluble cytochrome c-554, CycA, is not essential for photosynthetic electron transfer in Chlorobium tepidum.
We constructed a mutant lacking soluble cytochrome c-554 (CycA) by disruption of the cycA gene in the green sulfur bacterium Chlorobium tepidum. The mutant grew phototrophically with a growth rate slower than that of the wild type, suggesting that CycA is not essential for photosynthetic electron transfer even though CycA is known to work as an electron donor to the reaction center. The re-reduction of photo-oxidized cytochrome c(z) by quinol oxidoreductase was inhibited almost completely by the addition of stigmatellin in the mutant cells. This result indicates that, in the mutant cells, the linear electron transfer can occur from the quinol oxidoreductase to cytochrome c(z), and to reaction center P840 with no participation of CycA.
Department of Biology, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
Yusuke
Y
Tsukatani
Ryo
R
Miyamoto
Shigeru
S
Itoh
Hirozo
H
Oh-oka
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D041883:Chlorobium / Q000235:genetics / Q000254:growth & development*; D003574:Cytochrome c Group / Q000235:genetics / Q000378:metabolism*; D004579:Electron Transport / Q000187:drug effects / Q000235:genetics; D009154:Mutation; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics / Q000378:metabolism*; D011090:Polyenes / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D003574:Cytochrome c Group; D045322:Photosynthetic Reaction Center Complex Proteins; D011090:Polyenes; C022302:cytochrome C-552; C041573:stigmatellin