Do photosynthetic bacteria contain cytochrome c1?
A method is described for characterizing, c-type cytochromes in bacterial membrane preparations according to molecular weight on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Applied to the photosynthetic bacterium Rhodopseudomonas sphaeroides this technique is used, together with spectroscopic measurements, to demonstrate that a membrane-bound cytochrome c of mol.wt. 30000 is active in photosynthetic electron transport in addition to the well-known soluble cytochrome, cytochrome c2. The membrane cytochrome has a midpoint potential (E'0) at pH 7 of +290 mV, as compared with +360 mV for purified cytochrome c2. Its alpha-band has a peak near 552 nm, as compared with 550 nm for cytochrome c2. Evidence is presented that chromatophores contain roughly equal amounts of the two cytochromes.
D020130:Bacterial Chromatophores / Q000032:analysis; D002462:Cell Membrane / Q000032:analysis; D003574:Cytochrome c Group / Q000031:analogs & derivatives*; D003575:Cytochromes c1 / Q000032:analysis*; D004591:Electrophoresis, Polyacrylamide Gel; D008970:Molecular Weight; D010084:Oxidation-Reduction; D010788:Photosynthesis; D012242:Rhodobacter sphaeroides / Q000032:analysis*; D013053:Spectrophotometry
D003574:Cytochrome c Group; D003575:Cytochromes c1