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

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

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Radioactivity eventually destined for the chromatophore membrane of Rhodopseudomonas sphaeroides was shown in pulse-chase studies to appear first in a distinct pigmented fraction. This material formed an upper pigmented band which sedimented more slowly than chromatophores when cell-free extracts were subjected directly to rate-zone sedimentation on sucrose density gradients. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the purified fraction contained polypeptide bands of the same mobility as light-harvesting bacteriochlorophyll a and reaction center-associated protein components of chromatophores; these were superimposed upon cytoplasmic membrane polypeptides. The pulse-chase relation was confined mainly to the polypeptide components of these pigment-protein complexes. It is suggested that the isolated fraction may be derived from sites at which new membrane invagination is initiated.

Original languageEnglish (US)
Pages (from-to)210-220
Number of pages11
JournalBBA - Biomembranes
Issue number2
StatePublished - Aug 7 1979


All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Cell Biology


  • (Rps. sphaeroides)
  • Bacteriochlorophyll-protein complex
  • Chromatophore
  • Membrane synthesis

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