title: Excitation energy transfer in Rhodopseudomonas sphaeroides chromatophore membranes fused with liposomes.
abstract: The role of phospholipid in the structural organization of the light-harvesting complexes of Rhodopseudomonas sphaeroides was examined in photosynthetic (chromatophore) membrane vesicles fused with liposomes. Photochemically active preparations with progressive phospholipid enrichment up to greater than 15-fold were obtained by both polyethylene glycol- and acidic-pH-induced fusion. Their fluorescence emission at approximately 300 and 77 K was increased by 2-3.5-fold from the peripheral B800-850 antenna relative to that from the core B875 antenna. Up to 30-40% reduction in the efficiency of excitation energy transfer between B850 and B875 was also observed at 77 K suggesting a selective, phospholipid-induced dissociation of a portion of the B800-850 from the rest of the light-harvesting system.
mesh_terms: D020130:Bacterial Chromatophores / Q000378:metabolism*; D002499:Centrifugation, Density Gradient; D004735:Energy Transfer; D008081:Liposomes / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D010777:Photochemistry; D012242:Rhodobacter sphaeroides / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
chemical_list: D008081:Liposomes; D010743:Phospholipids