title: Complete amino acid sequence of the B875 light-harvesting protein of Rhodopseudomonas sphaeroides strain 2.4.1. Comparison with R26.1 carotenoidless-mutant strain.
abstract: The complete amino acid sequence was determined for the alpha- and beta-chains of the B875 light-harvesting protein purified from photosynthetic membranes of Rhodopseudomonas sphaeroides 2.4.1. The sequence of the B875-alpha-polypeptide was identical to that reported for the R26.1 carotenoidless mutant [(1985) Biochim. Biophys. Acta 806, 185-186] and contained 58 amino acid residues with a blocked methionine and a glutamic acid at the N- and C-termini, respectively. The B875-beta-polypeptide contained 48 amino acid residues with alanine and phenylalanine as respective N- and C-termini; although otherwise identical, the leucine at position 29 in the wild-type strain was replaced by proline in the mutant. This radical amino acid substitution occurred within the central hydrophobic domain of the beta-polypeptide chain and is thought to result in a weakening of the structure of the alpha/beta heterodimer since it was not possible to isolate the intact pigment-protein complex from the R26.1 mutant strain.
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001429:Bacteriochlorophylls / Q000378:metabolism; D002338:Carotenoids / Q000172:deficiency / Q000235:genetics; D045342:Light-Harvesting Protein Complexes; D046911:Macromolecular Substances; D009154:Mutation; D010788:Photosynthesis; D045322:Photosynthetic Reaction Center Complex Proteins; D012242:Rhodobacter sphaeroides / Q000201:enzymology* / Q000235:genetics; D013329:Structure-Activity Relationship
chemical_list: D001426:Bacterial Proteins; D001429:Bacteriochlorophylls; D045342:Light-Harvesting Protein Complexes; D046911:Macromolecular Substances; D045322:Photosynthetic Reaction Center Complex Proteins; D002338:Carotenoids