title: Molecular origins and consequences of High-800 LH2 in Roseobacter denitrificans.
abstract: Roseobacter denitrificans is a marine bacterium capable of using a wide variety of different metabolic schemes and in particular is an anoxygenic aerobic photosynthetic bacterium. In the work reported here we use a deletion mutant that we have constructed to investigate the structural origin of the unusual High-800 light-harvesting complex absorption in this bacterium. We suggest that the structure is essentially unaltered when compared to the usual nonameric complexes but that a change in the environment of the C(13:1) carbonyl group is responsible for the change in spectrum. We tentatively relate this change to the presence of a serine residue in the α-polypeptide. Surprisingly, the low spectral overlap between the peripheral and core light-harvesting systems appears not to compromise energy collection efficiency too severely. We suggest that this may be at the expense of maintaining a low antenna size.
authors: LISM, CNRS - Aix-Marseille University, Marseilles, France.
authors: Katia
authors: K
authors: Duquesne
authors: Cecile
authors: C
authors: Blanchard
authors: James N
authors: JN
authors: Sturgis
mesh_terms: D000595:Amino Acid Sequence; D001429:Bacteriochlorophylls / Q000737:chemistry; D001665:Binding Sites; D002942:Circular Dichroism; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry* / Q000235:genetics; D008954:Models, Biological; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000235:genetics; D010788:Photosynthesis; D012241:Rhodopseudomonas / Q000737:chemistry; D041904:Roseobacter / Q000737:chemistry* / Q000235:genetics; D013050:Spectrometry, Fluorescence; D013059:Spectrum Analysis, Raman
chemical_list: D001429:Bacteriochlorophylls; D045342:Light-Harvesting Protein Complexes; D010455:Peptides