title: Dark aerobic growth conditions induce the synthesis of a high midpoint potential cytochrome c8 in the photosynthetic bacterium Rubrivivax gelatinosus.
abstract: In several strains of the photosynthetic bacterium Rubrivivax gelatinosus, the synthesis of a high midpoint potential cytochrome is enhanced 4-6-fold in dark aerobically grown cells compared with anaerobic photosynthetic growth. This observation explains the conflicting reports in the literature concerning the cytochrome c content for this species. This cytochrome was isolated and characterized in detail from Rubrivivax gelatinosus strain IL144. The redox midpoint potential of this cytochrome is +300 mV at pH 7. Its molecular mass, 9470 kDa, and its amino acid sequence, deduced from gene sequencing, support its placement in the cytochrome c8 family. The ratio of this cytochrome to reaction center lies between 0.8 and 1 for cells of Rvi. gelatinosus grown under dark aerobic conditions. Analysis of light-induced absorption changes shows that this high-potential cytochrome c8 can act in vivo as efficient electron donor to the photooxidized high-potential heme of the Rvi. gelatinosus reaction center.
authors.affiliation: C.E.A./Cadarache-DSV-DEVM-Laboratoire de Bioénergétique Cellulaire, Saint-Paul-lez-Durance, France.
authors.forename: L
authors.initials: L
authors.lastname: Menin
authors.forename: M
authors.initials: M
authors.lastname: Yoshida
authors.forename: M
authors.initials: M
authors.lastname: Jaquinod
authors.forename: K V
authors.initials: KV
authors.lastname: Nagashima
authors.forename: K
authors.initials: K
authors.lastname: Matsuura
authors.forename: P
authors.initials: P
authors.lastname: Parot
authors.forename: A
authors.initials: A
authors.lastname: Verméglio
mesh_terms: D000332:Aerobiosis; D000595:Amino Acid Sequence; D001419:Bacteria / Q000201:enzymology* / Q000254:growth & development* / Q000378:metabolism / Q000528:radiation effects; D001426:Bacterial Proteins; D002458:Cell Fractionation; D003001:Cloning, Molecular; D003574:Cytochrome c Group / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification / Q000528:radiation effects; D004578:Electron Spin Resonance Spectroscopy; D004579:Electron Transport / Q000528:radiation effects; D004790:Enzyme Induction / Q000528:radiation effects; D008027:Light; D008969:Molecular Sequence Data; D019897:Periplasm / Q000737:chemistry / Q000528:radiation effects; D013053:Spectrophotometry
chemical_list: D001426:Bacterial Proteins; D003574:Cytochrome c Group; C017167:cytochrome C(551)