Light-harvesting pigment-protein complexes of Rhodopseudomonas sphaeroides forma sp. denitrificans.
The composition of the light-harvesting system of Rhodopseudomonas sphaeroides forma sp. denitrificans was investigated. When chromatophores were solubilized by sodium dodecyl sulfate (SDS) at 0 degrees C and subjected to SDS-polyacrylamide gel electrophoresis (SDS-PAGE), at least two B800-B850 pigment-protein complexes, three B870 pigment-protein complexes, a reaction center (RC) complex and two pigmented bands which contained B800, B850, and B870 were resolved. In the re-electrophoresis, the B870 pigment-protein complexes gave rise to a series of multiple pigmented bands. All of these multiple pigment-protein complexes showed almost the same polypeptide composition and absorption spectrum characteristic of the B870 complex. The apparent molecular weights of these B870 complexes showed a regular interval of about 7,000 indicating that these complexes were oligomers of a subunit. It was also found that a predominant B800-B850 pigment-protein complex could be degraded into a small complex via some intermediates. These results indicate that essentially two kinds of pigment-protein complexes construct the light-harvesting system of this bacteria and, upon treatment with SDS, these complexes are degraded into many classes of subunit aggregates showing a complicated profile of pigmented bands on the gel. Pigmented bands which contained both of B800-B850 and B870 complexes were considered to arise from occasional co-migration of distinct B800-B850 and B870 pigment-protein complexes.
D000332:Aerobiosis; D001426:Bacterial Proteins / Q000302:isolation & purification* / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D046911:Macromolecular Substances; D008970:Molecular Weight; D045322:Photosynthetic Reaction Center Complex Proteins; D012242:Rhodobacter sphaeroides / Q000378:metabolism*; D013053:Spectrophotometry
D001426:Bacterial Proteins; D046911:Macromolecular Substances; D045322:Photosynthetic Reaction Center Complex Proteins