Studies on the size and composition of the isolated light-harvesting B800-850 pigment-protein complex of Rhodopseudomonas capsulata

Shiozawa, Judith A.; Welte, Wolfram; Hodapp, Norbert; Drews, Gerhart

doi:10.1016/0003-9861(82)90573-2

Cited by 56 publications

(29 citation statements)

References 34 publications

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“…2). This was in accordance with earlier observations (8) and the finding that the B800 Bchl, which is a single Bchl molecule, is more labile than the B850 Bchl's (8,17).…”

Section: Resultssupporting

confidence: 93%

“…The protein patterns in SDS gels (Fig. 1) indicated a fast degradation of the 14,000-molecular-weight (14K) polypeptide, which does not bind pigments (8,17). The Bchl-binding 8K (,) and 10K (a) polypeptides were degraded more slowly.…”

Section: Resultsmentioning

confidence: 99%

“…R. capsulata ("Rhodobacter capsulatus") YS (obtained from B. Marrs), which is a photosyntheticnegative mutant (RC-, B875-, B800-850+) (8,17), was cultivated semi-aerobically in the dark at 30°C as previously described (17). The cells were harvested in the late logarithmic phase of growth.…”

mentioning

confidence: 99%

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Localization of the exposed N-terminal region of the B800-850 alpha and beta light-harvesting polypeptides on the cytoplasmic surface of Rhodopseudomonas capsulata chromatophores

Tadros¹,

Frank²,

Drews³

1986

J Bacteriol

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Proteinase K and trypsin were used to determine the orientation of the light-harvesting B800-850 a and , polypeptides within the chromatophores (inside-out membrane vesicles) of the mutant strain Y5 of Rhodopseudomonas capsulata. With proteinase K.7 amino acid residues of the B800-850 a polypeptide were cleaved off up to position Trp-7-Thr-8 of the N terminus, and 11 residues were cleaved off up to position Leu-1-Ser-12 of the 1 chain N terminus. The C termini of the B800-850 a and 1, polypeptides, including the hydrophobic transmembrane portions, remained intact. It is proposed that the N termini of the a and 13 subunits, each containing one transmembrane a-helical span, are exposed on the cytoplasmic membrane surface and the C termini are exposed to or directed toward the periplasm.

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“…2). This was in accordance with earlier observations (8) and the finding that the B800 Bchl, which is a single Bchl molecule, is more labile than the B850 Bchl's (8,17).…”

Section: Resultssupporting

confidence: 93%

Section: Resultsmentioning

confidence: 99%

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Localization of the exposed N-terminal region of the B800-850 alpha and beta light-harvesting polypeptides on the cytoplasmic surface of Rhodopseudomonas capsulata chromatophores

Tadros¹,

Frank²,

Drews³

1986

J Bacteriol

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“…The calculated Bchl-to-carotenoid molar ratio (1.6:1) in ARC6, which lacks pufQ and genes for RC and LHI, is different from the 3:1 Bchl-to-carotenoid molar ratio found in the isolated LHII complex (20). In strain ARC6(pBS3), which lacks genes for RC and LHI but contains pufQ, the Bchl-to-carotenoid molar ratio was found to be 3.8:1.…”

Section: ) (A)mentioning

confidence: 68%

Pleiotropic effects of localized Rhodobacter capsulatus puf operon deletions on production of light-absorbing pigment-protein complexes

Klug

Cohen

1988

J Bacteriol

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The polycistronic puf operon of Rhodobacter capsulatus encodes protein components for the photosynthetic reaction center and one of the two antenna complexes involved in the capture of light energy. We report here that deletions within specific puf genes alter the synthesis and/or assembly in the photosynthetic membranes of pigment-protein complexes not affected genetically by the deletion. The puJX gene is required for normal ratios of antenna complexes, and its deletion results in an increase of membrane-bound light-harvesting I (LHI) complex-specific proteins. Expression of pufQ in strains deleted for the genes encoding the LHI and the photosynthetic reaction center (RC) yields a novel A8. peak that has not been associated with any of the pigment-protein complexes described previously. While deletions in the RC-coding region resulted in decreased LHI absorbance, no quantitative alteration in membrane-bound LHI protein was observed, suggesting that an intact RC complex is required for correct assembly of LHI in the membrane.At least two different light-harvesting (antenna) complexes are involved in transferring energy to the photosynthetic reaction center (RC) in Rhodobacter capuslatus. The lightharvesting I (LHI) or B870 complex is found in the photosynthetic membrane in a constant molar ratio of about 12:1 relative to the RC complex (12), whereas the amount of LHII or B800-850 complex is variable and depends on growth conditions. Cells grown either under high oxygen tension or anaerobically under high light intensity lack the B800-850 complex, which can be found in 100-fold excess over RC in cultures under low oxygen tension (15,18,19). The antenna complexes and the RC each contain two pigment-binding proteins; non-pigment-binding proteins are additionally found in LHII and the RC complex. It has been suggested that the RC is associated with LHI oligomers in the membrane and that oligomers of the LHII complex surround both (9).The requirements for the correct assembly of pigments and pigment-binding proteins into photochemically functional complexes have been the subject of extensive investigation during recent years. Studies of mutant strains have shown that blocking the synthesis of some components of the photosynthetic apparatus can affect the synthesis and/or assembly of other components. Mutants blocked in early steps in bacteriochlorophyll (Bchl) synthesis lack pigmentbinding proteins in the membrane (13). Although mutants defective in late steps of Bchl synthesis can synthesize pigment-binding proteins and insert them into photosynthetic membranes, the proteins are unstable and undergo rapid turnover (7,13 Bacteriol., in press) that appears to be involved in the synthesis of Bchl (C. E. Bauer and B. L. Marrs, Proc. Natl. Acad. Sci. USA, in press) and a gene, X (26), of unknown function. In the present study, we examined the effects of specific puf operon deletions on the presence of various pigment-protein complexes in R. capsulatus photosynthetic membranes. Our results indicate that mutations in bo...

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“…The smallest functional unit (as defined by retention of the native absorption spectrum and efficient energy transfer among its pigments) usually has an apparent molecular weight of appx. 100 kDa (Picorel et al, 1984;Peters and Drews, 1983a;Shiozawa et al, 1982;Miller, 1982;Jay et al, 1984;Kramer et al, 1984). This corresponds to an aggregate of about six of each of the individual subunits, 12-18 molecules 'Dedicated to the memory of Warren L. Butler.…”

Section: Introductionmentioning

confidence: 99%

Circular Dichroism of Light‐harvesting Complexes From Purple Photosynthetic Bacteria*

Cogdell

Scheer

1985

Photochem & Photobiology

111

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Abstract-The CD spectra of a range of antenna complexes from several different species of purple photosynthetic bacteria were recorded in the wavelength range of 190 to 930 nm. Analysis of the far UV CD (190 to 250 nm) showed that in each case except for the B800-850 from Chr. vinosum the secondary structure of the light-harvesting complexes contains a large amount of a-helix ( 2 5 0 % ) and very little p-pleated sheet. This confirms the predictions of the group of Zuber of a high a-helical content based upon consideration of the primary structures of several antenna apoproteins. The CD spectra from the carotenoids and the bacteriochlorophylls show considerable variations depending upon the type of antenna complex. The different amplitude ratios in the CD spectrum for the bacteriochlorophyll Qy, Qx and Soret bands indicate not only different degrees of exciton coupling, but also a strong and variable hyperchromism (Scherz and Parson, 1984a, b).

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Studies on the size and composition of the isolated light-harvesting B800-850 pigment-protein complex of Rhodopseudomonas capsulata

Cited by 56 publications

References 34 publications

Localization of the exposed N-terminal region of the B800-850 alpha and beta light-harvesting polypeptides on the cytoplasmic surface of Rhodopseudomonas capsulata chromatophores

Localization of the exposed N-terminal region of the B800-850 alpha and beta light-harvesting polypeptides on the cytoplasmic surface of Rhodopseudomonas capsulata chromatophores

Pleiotropic effects of localized Rhodobacter capsulatus puf operon deletions on production of light-absorbing pigment-protein complexes

Circular Dichroism of Light‐harvesting Complexes From Purple Photosynthetic Bacteria*

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