Membranes of Rhodopseudomonas spheroides: Interactions of Chromatophores with the Cell Envelope
AUTOR(ES)
Niederman, Robert A.
RESUMO
Under carefully controlled ionic conditions, large-scale preparations of highly purified chromatophores and cell envelopes were obtained from phototrophically grown Rhodopseudomonas spheroides by zonal ultracentrifugation. The majority of the bacteriochlorophyll a was located in a single, discrete chromatophore band, whereas the envelopes were nearly devoid of photopigment. The envelope fraction contained substantial quantities of succinic dehydrogenase and cytochromes, confirming that phototrophically grown cells contain a photopigment-deficient cytoplasmic membrane. Magnesium at concentrations of 1.0 mM or higher caused chromatophores to reversibly aggregate with the cell envelope. Significant aggregation was also promoted by other divalent metals (Co2+ > Mn2+ > Ca2+ > Mg2+), but aggregation was less extensive with monovalent cations. These results account for the distribution of photopigments in two bands reported by others and further suggest that the photosynthetic apparatus of R. spheroides is located on membranes largely distinct from the cell wall-cytoplasmic membrane complex.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=246520Documentos Relacionados
- Bacteriophages of Rhodopseudomonas spheroides: Isolation and Characterization of a Rhodopseudomonas spheroides Bacteriophage
- Electron Microscopy of Chromatophores of Rhodopseudomonas spheroides
- Biosynthesis of Isoleucine and Valine in Rhodopseudomonas spheroides: Regulation of Threonine Deaminase Activity
- Bacteriochlorophyll and Heme Synthesis in Rhodopseudomonas spheroides: Possible Role of Heme in Regulation of the Branched Biosynthetic Pathway
- Topology and Growth of the Intracytoplasmic Membrane System of Rhodopseudomonas spheroides: Protein, Chlorophyll, and Phospholipid Insertion into Steady-State Anaerobic Cells
