Supramolecular organisation of the photosynthetic chain in anoxygenic bacteria.
This minireview summarizes our present view of the supramolecular organization of the photosynthetic apparatus of Rhodobacter sphaeroides and Rhodobacter capsulatus. These two species present a close association between two reaction centers (RCs), one cytochrome (cyt) bc(1) and one cyt c. In R. sphaeroides, the RCs are only partially surrounded by LH1 complexes. This open ring of LH1 complexes is required for an efficient photoinduced cyclic electron transfer only under conditions where the quinone pool totally reduced. When the quinone pool is partially oxidized, a closed ring of LH1 complexes around the RCs does not impair the exchange of quinone molecules between the RC and the cyt bc(1) complex. To explain the efficient photochemistry of the various species which possess a RC surrounded by a closed ring of LH, it is proposed that their quinone pool is partially oxidized even under anaerobic condition.
CEA/Cadarache DEVM-Laboratoire de Bioénergétique Cellulaire, UMR 163-CNRS-CEA, Univ-Méditerranée CEA1000, Saint Paul lez Durance, France. avermeglio@cea.fr
André
A
Verméglio
Pierre
P
Joliot
D001426:Bacterial Proteins; D003574:Cytochrome c Group / Q000737:chemistry; D004579:Electron Transport; D014450:Electron Transport Complex III / Q000737:chemistry; D045342:Light-Harvesting Protein Complexes; D008958:Models, Molecular; D010777:Photochemistry; D045322:Photosynthetic Reaction Center Complex Proteins; D016354:Rhodobacter capsulatus / Q000201:enzymology* / Q000254:growth & development; D012242:Rhodobacter sphaeroides / Q000201:enzymology* / Q000254:growth & development
D001426:Bacterial Proteins; D003574:Cytochrome c Group; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; C094744:light-harvesting complex 1, Rhodospirillum; D014450:Electron Transport Complex III