Membranes of Rhodopseudomonas sphaeroides. VI. Isolation of a fraction enriched in newly synthesized bacteriochlorophyll a-protein complexes

Niederman, Robert A.; Mallon, David E.; Parks, Lawrence C.

doi:10.1016/0005-2736(79)90161-5

Cited by 73 publications

(65 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For integration of peak areas in densitometric scans, appropriate peaks were traced with a manual digitizer interfaced to an Apple II Plus computer (kindly supplied by P. C. Kahn). been reported that ICM proteins are synthesized and assembled in constant amounts and proportions throughout the cell cycle in R. sphaeroides (8), studies in asynchronous cells suggested that B875 and reaction center proteins were assembled preferentially at apparent sites of initiation of ICM growth (20,21). These discrete membrane domains were isolated in an upper pigmented band after rate-zone sedimentation.…”

mentioning

confidence: 95%

“…* The pigmented membranes isolated in the upper band can contain up to 15% of the bacteriochlorophyll a in photoheterotrophically grown cells (20), and membrane surface labeling (14) as well as subcellular fractionation (14,20) studies are consistent with the possibility that these membrane fragments are derived from the cell periphery. Pulsechase studies with several amino acids (20,21) and labeling studies with the porphyrin precursor 8-aminolevulinic acid (12) have suggested that newly synthesized photochemical reaction centers and their associated core B875 lightharvesting complexes are assembled preferentially within the pigmented membrane domains isolated in the upper band. Furthermore, pulse-chase studies have suggested that these sites ultimately mature into ICM with the isolation characteristics of chromatophores.…”

mentioning

confidence: 99%

“…After mechanical disruption of photoheterotrophically grown cells, these differentiated regions of the membrane continuum can be separated by direct rate-zone sedimentation in sucrose density gradients (20,21). The ICM is isolated as a nearly uniform population of photosynthetically competent vesicles, termed chromatophores, which form a large pigmented band near the center of the gradient.…”

mentioning

confidence: 99%

“…Radiolabeling of membrane proteins was determined by measurement of trichloroacetic acid-precipitable radioactivity (21). Membrane samples were applied to filter paper disks, precipitated with '10% trichloroacetic acid at 0°C, washed with 5% trichloroacetic acid, and treated with acetone-methanol (7:2, vol/vol).…”

mentioning

confidence: 99%

“…This essentially limited the analysis to a level of cellular protein equivalent to that at the start of the chase. Where possible, specific radioactivities were fitted by eye to the hyperbolic pulse-chase relation established previously (20,21). .…”

mentioning

confidence: 99%

See 4 more Smart Citations

Role of apparent membrane growth initiation sites during photosynthetic membrane development in synchronously dividing Rhodopseudomonas sphaeroides

Reilly¹,

Niederman²

1986

J Bacteriol

View full text Add to dashboard Cite

Sites of intracytoplasmic membrane growth and temporal relations in the assembly of photosynthetic units were examined in synchronously dividing Rhodopseudomonas sphaeroides cells. After rate-zone sedimentation of cell-free extracts, apparent sites of initiation of intracytoplasmic membrane growth formed an upper pigmented band that sedimented more slowly than the intracytoplasmic membrane-derived chromatophore fraction. Throughout the cell cycle, the levels of the peripheral B800-850 light-harvesting pigment-protein complex relative to those of the core B875 complex in the upper pigmented fraction were only about half those of chromatophores. Pulse-labeling studies with L-[35SJmethionine indicated that the rates of assembly of proteins in the upper pigmented fraction were much higher than those of chromatophores throughout the cell cycle; rates for the reaction center polypeptides were estimated to be -3.5-fold higher than in chromatophores when the two membrane fractions were equalized on a protein basis. In pulse-chase studies, radioactivity of the reaction center and B875 polypeptides increased significantly in chromatophores and decreased in the upper pigmented band during cell division. These data suggest that the B875 reaction center cores of the photosynthetic units are inserted preferentially into sites-of membrane growth initiation isolated in the upper pigmented band and that the incomplete photosynthetic units are transferred from their sites of assembly into the intracytoplasmic membrane during cell division. These results suggested further that B800-850 is added directly to the intracytoplasmic membrane throughout the cell cycle.

show abstract

mentioning

confidence: 95%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Role of apparent membrane growth initiation sites during photosynthetic membrane development in synchronously dividing Rhodopseudomonas sphaeroides

Reilly¹,

Niederman²

1986

J Bacteriol

View full text Add to dashboard Cite

show abstract

Differential protein insertion into developing photosynthetic membrane Regions of Rhodopseudomonas sphaeroides

Inamine

Reilly

Niederman

1984

J of Cellular Biochemistry

Self Cite

View full text Add to dashboard Cite

Previous studies have suggested that much of the B800-850 light-harvesting bacteriochlorophyll a-protein complex is inserted directly into the intracytoplasmic photosynthetic membrane of Rhodopseudomonas sphaeroides. In contrast, the B875 light-harvesting and reaction center complexes are assembled preferentially at peripheral sites of photosynthetic membrane growth initiation. The basis for this apparent site-specific polypeptide insertion was examined during the inhibition of RNA and protein syntheses. The pulse labeling of polypeptides at the membrane growth initiation sites was significantly less sensitive to inhibition by rifampicin, chloramphenicol, or kasugamycin than in the intracytoplasmic or outer membranes. This suggests increased stability for the translation machinery at these membrane invagination sites. Similar differential effects in polypeptide insertion were observed during inhibition of bacteriochlorophyll synthesis through deprival of delta-aminolevulinate to R sphaeroides mutant H-5, which requires this porphyrin precursor. The pulse-labeling patterns observed during the inhibition of both RNA and pigment syntheses were consistent with the uncoupling of polypeptide insertion into the membrane invagination sites from their growth and maturation into intracytoplasmic membranes.

show abstract

Structure, Molecular Organization, and Biosynthesis of Membranes of Purple Bacteria

Drews¹,

Golecki²

Advances in Photosynthesis and Respiration

View full text Add to dashboard Cite

Membranes of Rhodopseudomonas sphaeroides. VI. Isolation of a fraction enriched in newly synthesized bacteriochlorophyll a-protein complexes

Cited by 73 publications

References 29 publications

Role of apparent membrane growth initiation sites during photosynthetic membrane development in synchronously dividing Rhodopseudomonas sphaeroides

Role of apparent membrane growth initiation sites during photosynthetic membrane development in synchronously dividing Rhodopseudomonas sphaeroides

Differential protein insertion into developing photosynthetic membrane Regions of Rhodopseudomonas sphaeroides

Structure, Molecular Organization, and Biosynthesis of Membranes of Purple Bacteria

Contact Info

Product

Resources

About